Skip deletion of safekeeper data if done previously.

[arssher]

To avoid re-listing s3 data during retries of tenant deletion with many branches.

[github-actions[bot]]

2466 tests run: 2345 passed, 0 failed, 121 skipped (full report)

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Flaky tests (2)

Postgres 15

• test_wal_restore_initdb: release
• test_wal_restore: release

Code coverage* (full report)

• functions: 28.8% (6781 of 23544 functions)
• lines: 47.6% (41258 of 86601 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
f08493f498dc56383410c7d22f77751c183f1590 at 2024-02-22T21:45:34.314Z :recycle:}

[jcsp]

Alternative: https://github.com/neondatabase/neon/pull/8253