tests: common log allow list for ancestor detach tests

[jcsp]

These log lines were repeated, and test_detached_receives_flushes_while_being_detached had an incomplete definition.

Example failure: https://neon-github-public-dev.s3.amazonaws.com/reports/pr-7531/8989511410/index.html#suites/a1c2be32556270764423c495fad75d47/992897d3a3369210

Checklist before requesting a review

• I have performed a self-review of my code.
• If it is a core feature, I have added thorough tests.
• Do we need to implement analytics? if so did you add the relevant metrics to the dashboard?
• If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section.

Checklist before merging

• Do not forget to reformat commit message to not include the above checklist

[github-actions]

3024 tests run: 2891 passed, 0 failed, 133 skipped (full report)

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Flaky tests (1)

Postgres 16

• test_vm_bit_clear_on_heap_lock: debug

Code coverage* (full report)

• functions: 31.2% (6256 of 20043 functions)
• lines: 46.7% (46934 of 100468 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
d98cf27 at 2024-05-07T19:55:27.729Z :recycle:}