bug symfony#52298 [HttpKernel] Update AbstractBundle.php, use !isset($this->path) (tacman)

This PR was merged into the 7.0 branch.

Discussion
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[HttpKernel] Update AbstractBundle.php, use !isset($this->path)

Fixes issue symfony#52292

| Q             | A
| ------------- | ---
| Branch?       | 7.0
| Bug fix?      | yes
| New feature?  no
| Deprecations?no
| Issues        | Fix symfony#52292
| License       | MIT

Check for isset rather than accessing the property before initialization.
```
!! Error {symfony#111
!! #message: "Typed property Symfony\Component\HttpKernel\Bundle\Bundle::$path must not be accessed before initialization"
!! #code: 0
!! #file: "./vendor/symfony/http-kernel/Bundle/AbstractBundle.php"
!! #line: 53
!! trace: {
```

Commits
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c59f4c5 Update AbstractBundle.php, use !isset($this->path)

Author: nicolas-grekas

src/Symfony/Component/HttpKernel/Bundle/AbstractBundle.php

@@ -50,7 +50,7 @@ public function getContainerExtension(): ?ExtensionInterface
 
     public function getPath(): string
     {
-        if (null === $this->path) {
+        if (!isset($this->path)) {
             $reflected = new \ReflectionObject($this);
             // assume the modern directory structure by default
             $this->path = \dirname($reflected->getFileName(), 2);