storage_controller: increase shard scan timeout

[erikgrinaker]

Problem

The node shard scan timeout of 1 second is a bit too aggressive, and we've seen this cause test failures. The scans are performed in parallel across nodes, and the entire operation has a 15 second timeout.

Resolves #9801.

Summary of changes

Increase the timeout to 5 seconds. This is still enough to time out on a network failure and retry successfully within 15 seconds.

[github-actions]

7029 tests run: 6721 passed, 0 failed, 308 skipped (full report)

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Flaky tests (9)

Postgres 17

• test_subscriber_synchronous_commit: release-arm64
• test_next_xid: debug-x86-64

Postgres 16

• test_prefetch[None]: release-arm64

Postgres 15

• test_prefetch[None]: release-x86-64, release-arm64
• test_readonly_node_gc: release-x86-64

Postgres 14

• test_prefetch[4]: release-arm64
• test_pull_timeline[True]: release-x86-64, release-arm64

Code coverage* (full report)

• functions: 30.8% (8265 of 26844 functions)
• lines: 47.8% (65177 of 136378 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
e7e00f8 at 2024-12-04T11:30:55.583Z :recycle:}