[Firestore] Change Firestore's release distro from source to binary for SPM

[ncooke3]

Context

• Change Firestore target definition to be a binary target rather than a source target
• Change gRPC and Abseil dependencies to point to new binary dependency repos
• Corresponding gRPC PR: [Release] Update Package.swift for 1.44.0 release google/grpc-binary#2
• Corresponding Abseil PR: [Release] Update Package.swift for 1.2021110200.0 release google/abseil-cpp-binary#2

Code Freeze Day + 1 Steps

Before Merging

• Wait for rc0 zip to be created
• Update and publish Abseil binary release using artifact from zip
  • abseil.xcframework
• Update and publish GRPC binary release using artifacts from zip
  • gRPC-C++.xcframework
  • gRPC-Core.xcframework
  • BoringSSL-GRPC.xcframework
• Update and publish Firestore binary release using artifact from zip
  • FirebaseFirestore.xcframework
• Update this branch with new Firestore checksum
• Confirm this branch resolves
• Confirm Firestore quickstart builds and functions
• Update CHANGELOG entry's version
• Update PR title and description
• Merge this PR when:
  • Approvals
  • Green CI

After Merging

• Move release (CocoaPods) tag to include this new commit

Fixes #6564

[google-oss-bot]

Coverage Report ¹

Affected Products

• FirebaseFirestore-iOS-FirebaseFirestore.framework

  Overall coverage changed from 88.27% (98e218b) to 88.24% (1965ef8) by -0.02%.

  Filename	Base (98e218b)	Merge (1965ef8)	Diff
  leveldb_key.cc	98.33%	98.14%	-0.20%
  leveldb_remote_document_cache.cc	96.41%	94.61%	-1.80%
  task.cc	94.78%	93.91%	-0.87%

Test Logs

• Base (98e218b): https://github.com/firebase/firebase-ios-sdk/actions/runs/4612242377
• Merge (1965ef8): https://github.com/firebase/firebase-ios-sdk/actions/runs/4620154140

1. https://storage.googleapis.com/firebase-sdk-metric-reports/8ay1ctY2lC.html

[ncooke3]

Green CI: https://github.com/firebase/firebase-ios-sdk/pull/11066/checks?sha=d8bdd5a86a8f141397186704859175bf57b970da

Now, will remove the dummy file that was used to trigger the Firestore CI.

[google-oss-bot]

Size Report ¹

Affected Products

• FirebaseFirestore

  Type	Base (a150f0b)	Merge (66513dd)	Diff
  CocoaPods	?	-51.5 kB	? (?)

Test Logs

• Merge (66513dd): https://github.com/firebase/firebase-ios-sdk/actions/runs/4608347530

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

[andrewheard]

Any luck with "Confirm Firestore quickstart builds and functions" ? Otherwise LGTM!

[ncooke3]

Any luck with "Confirm Firestore quickstart builds and functions" ? Otherwise LGTM!

I'm in the process of that right now! Will update in a few mins.

edit: @andrewheard, QS builds and functions.

[ncooke3]

Merging to re-tag for release while master is still clean. I can address any follow-up questions/concerns in a follow-up PR.