Add macrobenchmark module for sessions test app

[mrober]

Add macrobenchmark module for sessions test app. This is just the setup and the example startup benchmark. I will add more in the PerfAQS project, and write instructions in the readme then.

[github-actions]

📝 PRs merging into main branch

Our main branch should always be in a releasable state. If you are working on a larger change, or if you don't want this change to see the light of the day just yet, consider using a feature branch first, and only merge into the main branch when the code complete and ready to be released.

[github-actions]

Test Results

 1 058 files  ±0   1 058 suites  ±0   36m 4s ⏱️ +26s
 5 978 tests ±0   5 956 ✅ ±0  22 💤 ±0  0 ❌ ±0 
12 019 runs  ±0  11 975 ✅ ±0  44 💤 ±0  0 ❌ ±0 

Results for commit 489df8d. ± Comparison against base commit 61d972c.

♻️ This comment has been updated with latest results.

[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (61d972c) and merge commit (b0b62f1).

Test Logs

• Base (61d972c): https://github.com/firebase/firebase-android-sdk/actions/runs/15172813427
• Merge (b0b62f1): https://github.com/firebase/firebase-android-sdk/actions/runs/15189680202

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

[tejasd]

LGTM based on a sanity check - ./gradlew :firebase-sessions:benchmark:connectedCheck

[google-oss-bot]

Coverage Report ¹

Affected Products

• firebase-database

  Overall coverage changed from 50.21% (61d972c) to 50.22% (b0b62f1) by +0.01%.

  Filename	Base (61d972c)	Merge (b0b62f1)	Diff
  QueryParams.java	89.76%	90.36%	+0.60%

• firebase-sessions

  Overall coverage changed from 66.56% (61d972c) to 66.67% (b0b62f1) by +0.11%.

  Filename	Base (61d972c)	Merge (b0b62f1)	Diff
  RemoteSettings.kt	87.32%	88.73%	+1.41%

• firebase-firestore

  Filename	Base (61d972c)	Merge (b0b62f1)	Diff
  PatchMutation.java	98.39%	100.00%	+1.61%
  SetMutation.java	97.22%	94.44%	-2.78%

Test Logs

• Base (61d972c): https://github.com/firebase/firebase-android-sdk/actions/runs/15172813427
• Merge (b0b62f1): https://github.com/firebase/firebase-android-sdk/actions/runs/15189680202

1. https://storage.googleapis.com/firebase-sdk-metric-reports/cNKJffhO6G.html

[google-oss-bot]

Startup Time Report ¹

The report is too large (122,559 chars) to be displayed on GitHub. Please check this report on GCS.

1. https://storage.googleapis.com/firebase-sdk-metric-reports/sNfoa8ZCzQ/index.html