fix(meta): use object store's timestamp in SST retention sanity check

[zwang28]

I hereby agree to the terms of the RisingWave Labs, Inc. Contributor License Agreement.

What's changed and what's your intention?

In #18757 and #18779 the sanity check for newly added SSTs are introduced for commit_epoch and report_compaction.
As explained here, the issue is great clock drift may still trick the sanity check and cause correctness issue.

After second thoughts, I believe the additional read I/O overhead is a necessary trade-off to ensure correctness. This PR fixes the sanity check by using object timestamp from object store, ensuring consistency with the approach used during full GC.

The local object timestamp from compute node or compactor will be removed after this PR.

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• I have added test labels as necessary. See details.
• I have added fuzzing tests or opened an issue to track them. (Optional, recommended for new SQL features Sqlsmith: Sql feature generation #7934).
• My PR contains breaking changes. (If it deprecates some features, please create a tracking issue to remove them in the future).
• All checks passed in ./risedev check (or alias, ./risedev c)
• My PR changes performance-critical code. (Please run macro/micro-benchmarks and show the results.)

• My PR contains critical fixes that are necessary to be merged into the latest release. (Please check out the details)

Documentation

• My PR needs documentation updates. (Please use the Release note section below to summarize the impact on users)

Release note

If this PR includes changes that directly affect users or other significant modifications relevant to the community, kindly draft a release note to provide a concise summary of these changes. Please prioritize highlighting the impact these changes will have on users.