fix(wifi_scan): Fix some edge cases where WiFi Scan may fail

[me-no-dev]

Rework of #11075

This pull request focuses on memory management improvements and code simplification in the WiFiScan.cpp file. The most important changes include replacing delete[] with free(), using calloc() instead of new, and simplifying the scan completion check.

Memory management improvements:

• Replaced delete[] with free() and set the pointer to NULL in the _scanDone and scanDelete methods to prevent potential memory leaks. [1] [2]
• Replaced new with calloc() for allocating memory for WiFiScanClass::_scanResult to ensure the allocated memory is zero-initialized.

Code simplification:

• Simplified the scan completion check in the scanComplete method by removing unnecessary conditions and comments.

Other changes:

• Removed unnecessary increment of _scanStarted to prevent 0 from millis overflow.

Closes: #11075

[github-actions]

	Messages
📖	🎉 Good Job! All checks are passing!

👋 Hello me-no-dev, we appreciate your contribution to this project!

---

📘 Please review the project's Contributions Guide for key guidelines on code, documentation, testing, and more.

---

🖊️ Please also make sure you have read and signed the Contributor License Agreement for this project.

---

Click to see more instructions ...

This automated output is generated by the PR linter DangerJS, which checks if your Pull Request meets the project's requirements and helps you fix potential issues.

DangerJS is triggered with each push event to a Pull Request and modify the contents of this comment.

Please consider the following:
- Danger mainly focuses on the PR structure and formatting and can't understand the meaning behind your code or changes.
- Danger is not a substitute for human code reviews; it's still important to request a code review from your colleagues.
- To manually retry these Danger checks, please navigate to the Actions tab and re-run last Danger workflow.

Review and merge process you can expect ...

We do welcome contributions in the form of bug reports, feature requests and pull requests.

1. An internal issue has been created for the PR, we assign it to the relevant engineer.
2. They review the PR and either approve it or ask you for changes or clarifications.
3. Once the GitHub PR is approved we do the final review, collect approvals from core owners and make sure all the automated tests are passing.
- At this point we may do some adjustments to the proposed change, or extend it by adding tests or documentation.
4. If the change is approved and passes the tests it is merged into the default branch.

Generated by 🚫 dangerJS against 7553880

[github-actions]

Test Results

 76 files   76 suites   12m 42s ⏱️
 38 tests  38 ✅ 0 💤 0 ❌
241 runs  241 ✅ 0 💤 0 ❌

Results for commit 7553880.

♻️ This comment has been updated with latest results.

[github-actions]

Memory usage test (comparing PR against master branch)

The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.

Memory	FLASH [bytes]		FLASH [%]		RAM [bytes]		RAM [%]
Target	DEC	INC	DEC	INC	DEC	INC	DEC	INC
ESP32P4	0	⚠️ +270	0.00	⚠️ +0.04	0	⚠️ +16	0.00	⚠️ +0.06
ESP32S3	0	⚠️ +176	0.00	⚠️ +0.02	0	0	0.00	0.00
ESP32S2	0	⚠️ +180	0.00	⚠️ +0.02	0	0	0.00	0.00
ESP32C3	0	⚠️ +270	0.00	⚠️ +0.03	0	⚠️ +16	0.00	⚠️ +0.05
ESP32C6	0	⚠️ +270	0.00	⚠️ +0.03	0	⚠️ +16	0.00	⚠️ +0.04
ESP32	0	⚠️ +160	0.00	⚠️ +0.02	0	0	0.00	0.00

Click to expand the detailed deltas report [usage change in BYTES]

Target	ESP32P4		ESP32S3		ESP32S2		ESP32C3		ESP32C6		ESP32
Example	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM
libraries/WiFi/examples/FTM/FTM_Initiator	⚠️ +266	0	⚠️ +160	0	⚠️ +168	0	⚠️ +264	0	⚠️ +262	0	⚠️ +144	0
libraries/WiFi/examples/FTM/FTM_Responder	⚠️ +262	⚠️ +16	⚠️ +164	0	⚠️ +152	0	⚠️ +264	⚠️ +16	⚠️ +266	0	⚠️ +148	0
libraries/WiFi/examples/SimpleWiFiServer	⚠️ +260	⚠️ +16	⚠️ +164	0	⚠️ +148	0	⚠️ +262	0	⚠️ +262	0	⚠️ +148	0
libraries/WiFi/examples/WiFiAccessPoint	⚠️ +262	⚠️ +16	⚠️ +160	0	⚠️ +152	0	⚠️ +262	0	⚠️ +262	0	⚠️ +152	0
libraries/WiFi/examples/WiFiClient	⚠️ +262	0	⚠️ +124	0	⚠️ +152	0	⚠️ +260	0	⚠️ +260	0	⚠️ +140	0
libraries/WiFi/examples/WiFiClientBasic	⚠️ +270	0	⚠️ +164	0	⚠️ +152	0	⚠️ +268	⚠️ +16	⚠️ +270	⚠️ +16	⚠️ +140	0
libraries/WiFi/examples/WiFiClientConnect	⚠️ +260	⚠️ +16	⚠️ +156	0	⚠️ +152	0	⚠️ +264	⚠️ +16	⚠️ +264	0	⚠️ +144	0
libraries/WiFi/examples/WiFiClientEvents	⚠️ +262	⚠️ +16	⚠️ +128	0	⚠️ +148	0	⚠️ +264	⚠️ +16	⚠️ +264	0	⚠️ +148	0
libraries/WiFi/examples/WiFiClientStaticIP	⚠️ +262	⚠️ +16	⚠️ +160	0	⚠️ +156	0	⚠️ +262	0	⚠️ +264	0	⚠️ +144	0
libraries/WiFi/examples/WiFiExtender	⚠️ +262	⚠️ +16	⚠️ +132	0	⚠️ +156	0	⚠️ +262	⚠️ +16	⚠️ +264	0	⚠️ +144	0
libraries/WiFi/examples/WiFiIPv6	⚠️ +262	0	⚠️ +156	0	⚠️ +156	0	⚠️ +264	0	⚠️ +264	0	⚠️ +144	0
libraries/WiFi/examples/WiFiMulti	⚠️ +270	0	⚠️ +172	0	⚠️ +176	0	⚠️ +270	⚠️ +16	⚠️ +270	⚠️ +16	⚠️ +160	0
libraries/WiFi/examples/WiFiMultiAdvanced	⚠️ +270	0	⚠️ +176	0	⚠️ +172	0	⚠️ +270	⚠️ +16	⚠️ +270	⚠️ +16	⚠️ +156	0
libraries/WiFi/examples/WiFiScan	⚠️ +266	⚠️ +16	⚠️ +164	0	⚠️ +176	0	⚠️ +268	⚠️ +16	⚠️ +266	0	⚠️ +148	0
libraries/WiFi/examples/WiFiScanAsync	⚠️ +254	⚠️ +16	⚠️ +164	0	⚠️ +176	0	⚠️ +254	⚠️ +16	⚠️ +254	0	⚠️ +140	0
libraries/WiFi/examples/WiFiScanDualAntenna	⚠️ +266	⚠️ +16	⚠️ +156	0	⚠️ +172	0	⚠️ +266	⚠️ +16	⚠️ +266	0	⚠️ +148	0
libraries/WiFi/examples/WiFiScanTime	⚠️ +268	⚠️ +16	⚠️ +176	0	⚠️ +180	0	⚠️ +268	⚠️ +16	⚠️ +268	0	⚠️ +148	0
libraries/WiFi/examples/WiFiTelnetToSerial	⚠️ +270	0	⚠️ +168	0	⚠️ +160	0	⚠️ +270	⚠️ +16	⚠️ +270	⚠️ +16	⚠️ +160	0
libraries/WiFi/examples/WiFiUDPClient	⚠️ +262	0	⚠️ +160	0	⚠️ +156	0	⚠️ +264	0	⚠️ +264	0	⚠️ +156	0
libraries/WiFi/examples/WPS	-	-	⚠️ +156	0	⚠️ +120	0	⚠️ +264	⚠️ +16	⚠️ +264	0	⚠️ +148	0
libraries/WiFi/examples/WiFiBlueToothSwitch	-	-	⚠️ +172	0	-	-	⚠️ +262	⚠️ +16	⚠️ +262	⚠️ +16	⚠️ +148	0
libraries/WiFi/examples/WiFiClientEnterprise	-	-	⚠️ +164	0	⚠️ +156	0	⚠️ +262	⚠️ +16	⚠️ +262	0	⚠️ +132	0
libraries/WiFi/examples/WiFiSmartConfig	-	-	⚠️ +168	0	⚠️ +148	0	⚠️ +262	0	⚠️ +262	0	⚠️ +112	0