[CI] Increase unit test job timeout

[isarkis]

Unit test jobs in CI occasionally time out, even when tests are configured to retry. The existing job timeout of 2100 seconds does not provide sufficient time for a second attempt to complete after an initial test timeout of 1800 seconds. Increase the default job timeout to 2700 seconds to give a subsequent test attempts a fighting chance.

Issue: 470590965

[github-actions[bot]]

🤖 Gemini Suggested Commit Message

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ci: Increase unit test job timeout

Unit test jobs in CI occasionally time out, even when tests
are configured to retry. The existing job timeout of 2100
seconds does not provide sufficient time for a second attempt
to complete after an initial test timeout of 1800 seconds.
Increase the default job timeout to 2700 seconds to ensure
there is enough time for subsequent test attempts to finish.

Bug: 470590965

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