proxy: don't let one timeout eat entire retry budget

[cloneable]

This reduces the per-request timeout to 10sec while keeping the total retry duration at 1min.

Relates: neondatabase/cloud#15944

Problem

Summary of changes

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

[stradig]

LGTM, thanks!

[github-actions]

3829 tests run: 3719 passed, 0 failed, 110 skipped (full report)

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Flaky tests (1)

Postgres 15

• test_scrubber_physical_gc[4]: release-arm64

Code coverage* (full report)

• functions: 32.3% (7429 of 23006 functions)
• lines: 50.5% (60174 of 119170 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
2935d00 at 2024-09-05T10:51:42.045Z :recycle:}