dataconnect: .github/workflows/dataconnect_demo_app.yml added

[dconeybe]

Added GitHub actions to continuously test the firebase-dataconnect demo app that was recently added in #6561. Also tweak the gradle build script to better support cachability.

[github-actions]

Release note changes

No release note changes were detected. If you made changes that should be
present in the next release, ensure you've added an entry in the appropriate
CHANGELOG.md file(s).

[github-actions]

Vertex AI Mock Responses Check ⚠️

A newer major version of the mock responses for Vertex AI unit tests is available. update_responses.sh should be updated to clone the latest version of the responses: v5.2

[github-actions]

Test Results

 1 036 files  +   974   1 036 suites  +974   33m 12s ⏱️ + 32m 6s
 5 873 tests + 5 332   5 851 ✅ + 5 311  22 💤 +21  0 ❌ ±0 
11 831 runs  +10 749  11 787 ✅ +10 707  44 💤 +42  0 ❌ ±0 

Results for commit f4d74f6. ± Comparison against base commit 2190810.

[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (2190810) and merge commit (00766d8).

Test Logs

• Base (2190810): https://github.com/firebase/firebase-android-sdk/actions/runs/12189493565
• Merge (00766d8): https://github.com/firebase/firebase-android-sdk/actions/runs/12194316993

1. https://storage.googleapis.com/firebase-sdk-metric-reports/Xi7XhLpCG6.html

[google-oss-bot]

Coverage Report ¹

Affected Products

• firebase-firestore

  Overall coverage changed from 45.73% (2190810) to 45.73% (00766d8) by -0.00%.

  Filename	Base (2190810)	Merge (00766d8)	Diff
  SetMutation.java	97.22%	94.44%	-2.78%

• firebase-messaging

  Overall coverage changed from 84.19% (2190810) to 84.12% (00766d8) by -0.07%.

  Filename	Base (2190810)	Merge (00766d8)	Diff
  RequestDeduplicator.java	90.00%	80.00%	-10.00%

Test Logs

• Base (2190810): https://github.com/firebase/firebase-android-sdk/actions/runs/12189493565
• Merge (00766d8): https://github.com/firebase/firebase-android-sdk/actions/runs/12194316993

1. https://storage.googleapis.com/firebase-sdk-metric-reports/wPER4vn9NJ.html