tests: turn on safekeeper eviction by default

[jcsp]

Problem

Ahead of enabling eviction in the field, where it will become the normal/default mode, let's enable it by default throughout our tests in case any issues become visible there.

Summary of changes

• Make default extra_opts for safekeepers enable offload & deletion
• Set low timeouts in extra_opts so that tests running for tens of seconds have a chance to hit some of these background operations.

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]

3226 tests run: 3093 passed, 0 failed, 133 skipped (full report)

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Flaky tests (4)

Postgres 15

• test_isolation[None]: debug
• test_sharded_timeline_detach_ancestor: debug

Postgres 14

• test_subscriber_restart: release
• test_s3_eviction[0.2-True]: debug

Code coverage* (full report)

• functions: 32.7% (6985 of 21380 functions)
• lines: 50.1% (55035 of 109932 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
868c02d at 2024-07-17T21:29:29.833Z :recycle:}