[fix](cloud) Separate HTTP encoding for job recycle and check keys

[wyxxxcat]

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:
The HTTP key encoder incorrectly mapped JobRecycleKey to job_check_key, causing recycle job keys to use the check namespace. This change maps JobRecycleKey to job_recycle_key, adds the JobCheckKey HTTP mapping, and provides the string-returning overload for job_recycle_key. Unit test coverage was added for both key types.

Release note

None

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

[hello-stephen]

Cloud UT Coverage Report

Increment line coverage 100.00% (3/3) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	78.01% (2050/2628)
Line Coverage	65.67% (37386/56926)
Region Coverage	52.91% (34856/65883)
Branch Coverage	56.32% (11191/19870)