[Refactor] move `getPartitions` API into `icebergCatalog`

[dirtysalt]

Why I'm doing:

For all iceberg catalog implementations, the way to getPartitions are the same:

• scan metadata provided dbname,tblname, snapshotId
• with optional executorService

And with one pass scan, we can get both

• partition name
• and partition info

What I'm doing:

Fixes #issue

What type of PR is this:

• [ ] BugFix
• [ ] Feature
• [ ] Enhancement
• [x] Refactor
• [ ] UT
• [ ] Doc
• [ ] Tool

Does this PR entail a change in behavior?

• [ ] Yes, this PR will result in a change in behavior.
• [x] No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• [ ] Interface/UI changes: syntax, type conversion, expression evaluation, display information
• [ ] Parameter changes: default values, similar parameters but with different default values
• [ ] Policy changes: use new policy to replace old one, functionality automatically enabled
• [ ] Feature removed
• [ ] Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• [ ] I have added test cases for my bug fix or my new feature
• [ ] This pr needs user documentation (for new or modified features or behaviors)
  • [ ] I have added documentation for my new feature or new function
• [ ] This is a backport pr

Bugfix cherry-pick branch check:

• [x] I have checked the version labels which the pr will be auto-backported to the target branch
  • [ ] 3.3
  • [ ] 3.2
  • [ ] 3.1
  • [ ] 3.0
  • [ ] 2.5

[sonarcloud[bot]]

Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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[github-actions[bot]]

[Java-Extensions Incremental Coverage Report]

:white_check_mark: pass : 0 / 0 (0%)

[github-actions[bot]]

[FE Incremental Coverage Report]

:white_check_mark: pass : 88 / 104 (84.62%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
:large_blue_circle:	com/starrocks/connector/iceberg/CachingIcebergCatalog.java	18	25	72.00%	[94, 203, 204, 261, 262, 386, 387]
:large_blue_circle:	com/starrocks/connector/iceberg/IcebergCatalog.java	60	69	86.96%	[183, 184, 194, 195, 234, 235, 243, 244, 251]
:large_blue_circle:	com/starrocks/connector/iceberg/IcebergMetadata.java	10	10	100.00%	[]

[github-actions[bot]]

[BE Incremental Coverage Report]

:white_check_mark: pass : 0 / 0 (0%)

[dirtysalt]

@mergify backport branch-3.4

[mergify[bot]]

backport branch-3.4

✅ Backports have been created

* [#53116 [Refactor] move `getPartitions` API into `icebergCatalog` (backport #53007)](https://github.com/StarRocks/starrocks/pull/53116) has been created for branch `branch-3.4`