Auto update GMA deps on iOS.

[jonsimantov]

Description

Provide details of the change, and generalize the change in the PR title above.

Requires some custom code to handle the old 'admob' iOS SDK.

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Testing

Describe how you've tested these changes. Link any manually triggered Integration tests or CPP binary SDK Packaging Github Action workflows, if applicable.

Ran manually, it updated everything correctly and skipped the old admob SDK.

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Type of Change

Place an x the applicable box:

• Bug fix. Add the issue # below if applicable.
• New feature. A non-breaking change which adds functionality.
• Other, such as a build process or documentation change.

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Notes

• Bug fixes and feature changes require an update to the Release Notes section of release_build_files/readme.md.
• Read the contribution guidelines CONTRIBUTING.md.
• Changes to the public API require an internal API review. If you'd like to help us make Firebase APIs better, please propose your change in a feature request so that we can discuss it together.

[DellaBitta]

Does this mean the older AdMob SDK will now be updated?

[jonsimantov]

Does this mean the older AdMob SDK will now be updated?

No:

1. You'll see I added a flag that makes it not update any iOS versions that contain "cppsdk"
2. The old Android SDK uses firebase-ads, which is still in the "don't update" list.

[github-actions]

Integration test with FLAKINESS (succeeded after retry)

Requested by @jonsimantov on commit 7911900
Last updated: Wed Jan 25 13:36 PST 2023
View integration test log & download artifacts

Failures	Configs
firestore	[TEST] [FLAKINESS] [Android] [1/3 os: windows] [1/2 android_device: android_target] (1 failed tests)   CRASH/TIMEOUT
gma	[TEST] [FLAKINESS] [Android] [1/3 os: ubuntu] [1/2 android_device: android_target] (1 failed tests)   FirebaseGmaTest.TestRewardedAdLoadEmptyRequest [TEST] [FLAKINESS] [Android] [2/3 os: ubuntu windows] [1/2 android_device: android_target] (1 failed tests)   FirebaseGmaTest.TestRewardedAdLoad [TEST] [FLAKINESS] [Android] [All 3 os] [1/2 android_device: android_target] (1 failed tests)   FirebaseGmaTest.TestRewardedAdStress
messaging	[TEST] [FLAKINESS] [Android] [1/3 os: macos] [1/2 android_device: android_target] (1 failed tests)   CRASH/TIMEOUT

Add flaky tests to go/fpl-cpp-flake-tracker