Patch abseil-cpp to ignore deprecated errors in new Xcode.

[jonsimantov]

The current version of abseil-cpp (used by grpc) uses some deprecated builtins, which cause warnings that make the build fail on Xcode 15 (due to warnings-as-errors).

Until grpc is updated, this PR will work around the issue by adding a patch to abseil-cpp to turn off that warning for that file.

[google-oss-bot]

Coverage Report ¹

Affected Products

• FirebaseFirestore-iOS-FirebaseFirestoreInternal.framework

  Overall coverage changed from 88.20% (48a77e3) to 88.08% (d85edf8) by -0.11%.

  Filename	Base (48a77e3)	Merge (d85edf8)	Diff
  exception.cc	84.21%	23.68%	-60.53%
  leveldb_key.cc	98.14%	98.82%	+0.69%
  leveldb_persistence.cc	93.59%	92.31%	-1.28%
  lru_garbage_collector.cc	96.06%	91.34%	-4.72%
  ordered_code.cc	94.39%	93.90%	-0.49%
  status.cc	75.89%	73.05%	-2.84%
  write_stream.cc	91.55%	94.37%	+2.82%

Test Logs

• Base (48a77e3): https://github.com/firebase/firebase-ios-sdk/actions/runs/8205462221
• Merge (d85edf8): https://github.com/firebase/firebase-ios-sdk/actions/runs/8208924677

1. https://storage.googleapis.com/firebase-sdk-metric-reports/Azhbxoa1rk.html

[dconeybe]

LGTM. Just one minor change requested.

[Vyazovoy]

Hi, @jonsimantov! Doesn't #12538 means that your changes should be reverted?