ci: enable ITQueryCountTest in CI, since the project is whitelisted for COUNT

[dconeybe]

No description provided.

[dconeybe]

aggregateQueryInATransactionShouldLockTheCountedDocuments is failing on kokoro:

java.lang.AssertionError: expected java.util.concurrent.ExecutionException to be thrown, but nothing was thrown
	at com.google.cloud.firestore.ITQueryCountTest.aggregateQueryInATransactionShouldLockTheCountedDocuments(ITQueryCountTest.java:238)

I need to check if this is a bug in the backend or a faulty test. This test passes against the Firestore emulator.

Here is the line in the test that is failing:

java-firestore/google-cloud-firestore/src/test/java/com/google/cloud/firestore/ITQueryCountTest.java

Line 238 in a7e90dd

executionException = assertThrows(ExecutionException.class, documentSetTask::get);

I've opened b/248152832 to investigate.

[dconeybe]

I've just disabled aggregateQueryInATransactionShouldLockTheCountedDocuments for now, so at least the rest of the tests can be run. I've opened #1043 to investigate and re-enable it.