fix(pageserver): properly propagate missing key error for vectored get

[skyzh]

Problem

Some part of the code requires missing key error to be propagated to the code path correctly (i.e., aux key range scan). Currently, it's an anyhow error.

• remove stuck_lsn from the missing key error.
• as a result, when matching missing key, we do not distinguish the case stuck_lsn = false/true.
• vectored get now use the unified missing key error.

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]

2856 tests run: 2735 passed, 0 failed, 121 skipped (full report)

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Flaky tests (1)

Postgres 15

• test_vm_bit_clear_on_heap_lock: debug

Code coverage* (full report)

• functions: 28.1% (6601 of 23486 functions)
• lines: 46.8% (46868 of 100235 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
0f98799 at 2024-05-01T17:04:05.773Z :recycle:}

[skyzh]

removed stuck_at_lsn and vectored_get field, maybe we will add a key_range field in the future, but for now, not adding it to avoid large copies (keyspace can be large with multiple partitions).