dataconnect: QuerySubscriptionIntegrationTest.kt: fix flaky test using backgroundScope

[dconeybe]

Fix a flaky test by ensuring that the query subscription started in backgroundScope gets its first result before continuing the test.

[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.

[google-oss-bot]

Coverage Report ¹

Affected Products

No changes between base commit (2cdac31) and merge commit (a77af5e).

Test Logs

• Base (2cdac31): https://github.com/firebase/firebase-android-sdk/actions/runs/14198235275
• Merge (a77af5e): https://github.com/firebase/firebase-android-sdk/actions/runs/14211083288

1. https://storage.googleapis.com/firebase-sdk-metric-reports/ndTXgpkKi1.html

[github-actions]

Test Results

   66 files  ±0     66 suites  ±0   1m 21s ⏱️ +4s
  552 tests ±0    551 ✅ ±0  1 💤 ±0  0 ❌ ±0 
1 104 runs  ±0  1 102 ✅ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit a89d7ca. ± Comparison against base commit 2cdac31.

[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (2cdac31) and merge commit (a77af5e).

Test Logs

• Base (2cdac31): https://github.com/firebase/firebase-android-sdk/actions/runs/14198235275
• Merge (a77af5e): https://github.com/firebase/firebase-android-sdk/actions/runs/14211083288

1. https://storage.googleapis.com/firebase-sdk-metric-reports/H4rB5SEppL.html

[Copilot]

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Files not reviewed (1)

• firebase-dataconnect/src/androidTest/kotlin/com/google/firebase/dataconnect/QuerySubscriptionIntegrationTest.kt: Language not supported