[fix](cloud) Avoid deleting nonexistent delete bitmap files

[wyxxxcat]

What problem does this PR solve?

When recycling rowset data, the recycler treated a missing versioned delete bitmap meta key as "not packed" and added the standalone delete bitmap object path to the delete_files request. This caused unnecessary delete object requests for <rowset_id>_delete_bitmap.db even when no delete bitmap storage metadata existed.

The fix makes delete bitmap storage handling explicit: missing meta, FDB storage, standalone file storage, and packed file storage are distinguished. The recycler now only deletes <rowset_id>_delete_bitmap.db when the metadata explicitly indicates a standalone delete bitmap file.

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

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Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[hello-stephen]

Thank you for your contribution to Apache Doris.
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Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[wyxxxcat]

run buildall

[liaoxin01]

LGTM

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.