[Failing Test]: testE2EBigtableWriteWith[...]Failures flaky

### What happened?

These error handler tests have long been flaky. For example, in the last 2 weeks, PostCommit Java Dataflow V2 failed 10 times, 6 due to one test failed in these five:

testE2EBigtableWriteWithInvalidColumnFamilyFailures

testE2EBigtableWriteWithEmptyMutationFailures

testE2EBigtableWriteWithEmptyRowFailures

testE2EBigtableWriteWithInvalidTimestampFailures

testE2EBigtableWriteWithOversizedQualifierFailures

Example error:

```
java.lang.RuntimeException: org.apache.beam.sdk.util.UserCodeException: java.lang.AssertionError: Write to error Sink/Combine/Flatten.PCollections.out:
Expected: <2L>
but: was <1L>
at org.apache.beam.sdk.util.UserCodeException.wrap(UserCodeException.java:39)
at org.apache.beam.sdk.testing.PAssert$DefaultConcludeFn$DoFnInvoker.invokeProcessElement(Unknown Source)
...
Caused by: java.lang.AssertionError: Write to error Sink/Combine/Flatten.PCollections.out:
Expected: <2L>
but: was <1L>
at org.apache.beam.sdk.testing.PAssert$PAssertionSite.capture(PAssert.java:176)
at org.apache.beam.sdk.testing.PAssert.thatSingleton(PAssert.java:499)
at org.apache.beam.sdk.testing.PAssert.thatSingleton(PAssert.java:491)
at org.apache.beam.sdk.io.gcp.bigtable.BigtableWriteIT.failureTest(BigtableWriteIT.java:341)
at org.apache.beam.sdk.io.gcp.bigtable.BigtableWriteIT.testE2EBigtableWriteWithInvalidColumnFamilyFailures(BigtableWriteIT.java:164)
```

it appears to be related to how elements are bundled, as Dataflow v1 / v2 / direct runner has different flaky rate (Dataflow v2 test fails most frequently)

### Issue Failure

Failure: Test is flaky

### Issue Priority

Priority: 2 (backlog / disabled test but we think the product is healthy)

### Issue Components

- [ ] Component: Python SDK
- [X] Component: Java SDK
- [ ] Component: Go SDK
- [ ] Component: Typescript SDK
- [X] Component: IO connector
- [ ] Component: Beam YAML
- [ ] Component: Beam examples
- [ ] Component: Beam playground
- [ ] Component: Beam katas
- [ ] Component: Website
- [ ] Component: Infrastructure
- [ ] Component: Spark Runner
- [ ] Component: Flink Runner
- [ ] Component: Samza Runner
- [ ] Component: Twister2 Runner
- [ ] Component: Hazelcast Jet Runner
- [ ] Component: Google Cloud Dataflow Runner