chore(vm-image): specify sql exporter listen port

[skyzh]

Problem

Extracted from #7514, 9399 is the default port. We want to specify it b/c we will start a second sql exporter for autoscaling agent soon.

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

[github-actions]

2796 tests run: 2675 passed, 0 failed, 121 skipped (full report)

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Flaky tests (2)

Postgres 16

• test_download_remote_layers_api: debug

Postgres 14

• test_pageserver_recovery: debug

Code coverage* (full report)

• functions: 28.3% (6547 of 23143 functions)
• lines: 46.9% (46226 of 98460 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
ed41f03 at 2024-04-26T18:44:08.053Z :recycle:}