tests: longer timeout in test_delete_timeline_client_hangup

[jcsp]

Problem

This test waits for a request to finish, and then expects deletion to complete almost immediately. The request completes, but it's a 202, the timeline is still deleting in the background: we need to be more patient.

Summary of changes

• Adjust iterations from 2 to 10 when waiting for deletion

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]

5013 tests run: 4855 passed, 0 failed, 158 skipped (full report)

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Flaky tests (2)

Postgres 17

• test_pageserver_compaction_smoke: release-arm64

Postgres 14

• test_ondemand_wal_download_in_replication_slot_funcs: release-arm64

Code coverage* (full report)

• functions: 31.4% (7484 of 23798 functions)
• lines: 49.8% (60087 of 120696 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
3d1c3b9 at 2024-09-30T10:53:25.650Z :recycle:}