fix(pageserver): handle lsn lease requests for unnormalized lsns

[yliang412]

Fixes #9098.

Problem

See #9098 (comment).

Related

A similar problem happened with branch creation, which was discussed here and fixed by #2529.

Summary of changes

• Normalize the lsn on pageserver side upon lsn lease request, stores the normalized LSN.

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]

4986 tests run: 4822 passed, 0 failed, 164 skipped (full report)

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Flaky tests (5)

Postgres 17

• test_pageserver_compaction_smoke: release-x86-64
• test_ondemand_wal_download_in_replication_slot_funcs: release-x86-64
• test_subscriber_restart: release-x86-64

Postgres 16

• test_subscriber_restart: release-x86-64

Postgres 14

• test_subscriber_restart: release-x86-64

Code coverage* (full report)

• functions: 32.2% (7478 of 23255 functions)
• lines: 50.0% (60245 of 120558 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
59e252e at 2024-09-25T02:16:18.721Z :recycle:}