[bvolpato]

BigQuery Storage Write API writers remove rejected payloads and timestamps before retrying a batch, but leave failsafe rows in their original positions. When withFormatRecordOnFailureFunction is set, a later serialization error can select the wrong original row for the failure output, duplicating one record and omitting another.

This change filters failsafe rows alongside payloads and timestamps in both writers. Nullable entries used for protobuf-to-TableRow fallback are preserved. The API defines row-error indexes relative to the current request.

Local regression validation passed with controlled append responses. A recorded live BigQuery run also reproduced the misattribution after a partial row-error response. That response size was observed in the run and is not an API guarantee.

Run the GCP module tests with:

./gradlew :sdks:java:io:google-cloud-platform:test

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