[FirebaseCoreInternal] Guard against invalid indexing into RingBuffer type

[ncooke3]

Context

An issue was reported where the issue's crash report suggests an index out of bounds exception in the RingBuffer type. This type is used by FirebaseCoreInternal's heartbeat component. RingBuffer internally manages an insertion index that is incremented/decremented to always be within the inner array's bounds. In the reported issue, that assumption was being broken for some reason.

To prevent the crash, the crashing RingBuffer API is converted to a throwing method that throws an error if the insertion index is out of bounds. This is gracefully handled in the calling context to reset the ring buffer in an effort to return things to a normal state.

Fixes #10025

[google-oss-bot]

Coverage Report ¹

Affected Products

• FirebaseFirestore-iOS-FirebaseFirestore.framework

  Overall coverage changed from 88.40% (7e3548b) to 88.42% (b611821) by +0.02%.

  Filename	Base (7e3548b)	Merge (b611821)	Diff
  leveldb_key.cc	98.14%	98.63%	+0.49%

Test Logs

• Base (7e3548b): https://github.com/firebase/firebase-ios-sdk/actions/runs/2715554381
• Merge (b611821): https://github.com/firebase/firebase-ios-sdk/actions/runs/2719928922

1. https://storage.googleapis.com/firebase-sdk-metric-reports/a47oqzhoa8.html