Add expected count to Target

[milaGGL]

#no-changelog

• make expected_count optional in proto
• add expected_count to Target only when resume token is presented(and set has_expected_count to true)
• port expected_count related spec tests from web and make sure it is not gonna break

[google-oss-bot]

Coverage Report ¹

Affected Products

• FirebaseFirestore-iOS-FirebaseFirestore.framework

  Overall coverage changed from 88.26% (61db372) to 88.22% (fe7b3e0) by -0.04%.

  Filename	Base (61db372)	Merge (fe7b3e0)	Diff
  bloom_filter.nanopb.cc	?	0.00%	?
  firebase_metadata_provider_apple.mm	86.96%	100.00%	+13.04%
  firestore.nanopb.cc	35.71%	35.73%	+0.01%
  remote_store.cc	90.86%	91.06%	+0.20%
  serializer.cc	91.05%	91.09%	+0.04%
  target_data.cc	40.63%	48.00%	+7.37%
  task.cc	94.78%	93.91%	-0.87%
  wrappers.nanopb.cc	9.40%	11.11%	+1.71%
  write.nanopb.cc	60.23%	61.27%	+1.04%
  write_stream.cc	91.55%	94.37%	+2.82%

Test Logs

• Base (61db372): https://github.com/firebase/firebase-ios-sdk/actions/runs/4285242529
• Merge (fe7b3e0): https://github.com/firebase/firebase-ios-sdk/actions/runs/4287862545

1. https://storage.googleapis.com/firebase-sdk-metric-reports/Lu5Na6uOSR.html

[dconeybe]

Note: Merge in the base branch after you merge #10874 (Add golden tests for BloomFilter). Doing so will fix the "firestore / cmake (ubuntu-latest) (pull_request)" GitHub action, which is failing because CommonCrypto is not available on Linux (https://github.com/firebase/firebase-ios-sdk/actions/runs/4318256537/jobs/7536444988)