* [Crashlytics] Fix build issues on visionOS
Fixed Firebase Crashlytics SDK build issues for visionOS, along with
corresponding unit test changes. This also resolves build issues with
the underlying Firebase Sessions SDK.
* Allow pod-lib-lint warnings for Firebase Sessions
* VisionOS deprecated kernel api update
* Moved `swift(>=5.9)` check to separate `#if` statement
* Move swift(>=5.9) check in SessionStartEventTests
* adding comment, declear and use internal macro
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Co-authored-by: Andrew Heard <andrewheard@google.com>
