test(bigquerystorage): increase await timeout for createReadSession to 1 minute

[lqiu96]

Description

Increases the await() timeout to 1 minute in ITBigQueryStorageTest (v1beta1, v1beta2) and adds the 1-minute retry logic to the production v1 test helper (Helper.processRowsAtSnapshot) when creating read sessions.

Context

In CI environments, table metadata propagation from bigquery.googleapis.com to bigquerystorage.googleapis.com can take longer than 10 seconds, causing ConditionTimeoutException or NotFoundException test flakes (e.g., in sponge/b1dc622b-9c70-41cb-953e-74c2dfbb3f31).

Setting a 1-minute retry ceiling:

• Provides sufficient buffer for metadata propagation across busy CI runners.
• Ensures consistency across v1, v1beta1, and v1beta2 test suites.
• Matches the 1-minute timeout used elsewhere in the test suite (e.g. job.waitFor(..., RetryOption.totalTimeoutDuration(Duration.ofMinutes(1)))).
• Adds zero extra latency to successful runs, as await() returns immediately upon session creation.

[gemini-code-assist]

Code Review

This pull request increases the await timeout from 10 seconds to 1 minute in the integration tests for both v1beta1 and v1beta2 BigQuery Storage clients, specifically within the ProcessRowsAtSnapshot helper method. This change allows more time for newly-created tables to propagate. There are no review comments, and I have no feedback to provide.