Fix the heartbeat integration test in Firestore

[var-const]

It was broken by #2012

[google-oss-bot]

Binary Size Report

Affected SDKs

No changes between base commit (5bc4d96) and head commit (8a674fbb).

Test Logs

• Base (5bc4d964): https://android-ci.firebaseopensource.com/view/gcs/android-ci/logs/postsubmit-binary-size/1311345767755026435
• Head (8a674fbb): https://android-ci.firebaseopensource.com/view/gcs/android-ci/pr-logs/pull/firebase_firebase-android-sdk/2024/binary-size/1311389179472515076

Notes

Head commit (8a674fbb) is created by Prow via merging commits: 5bc4d96 e09fcaa.

[google-oss-bot]

Coverage Report

Affected SDKs

No changes between base commit (5bc4d96) and head commit (8a674fbb).

Test Logs

• Base (5bc4d964): https://android-ci.firebaseopensource.com/view/gcs/android-ci/logs/postsubmit-check-coverage/1311345767755026432
• Head (8a674fbb): https://android-ci.firebaseopensource.com/view/gcs/android-ci/pr-logs/pull/firebase_firebase-android-sdk/2024/check-coverage-changed/1311389179472515077

Notes

HTML coverage reports can be produced locally with ./gradlew <product>:checkCoverage.
Report files are located at <product-build-dir>/reports/jacoco/.

Head commit (8a674fbb) is created by Prow via merging commits: 5bc4d96 e09fcaa.

[google-oss-bot]

@var-const: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
smoke-tests	e09fcaa	link	/test smoke-tests

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