[Enhancement] Reduce metadata lock scope for files() schema pushdown (backport #63796)

[mergify]

Why I'm doing:

Schema inference for files() (filesystem listing + backend RPC) previously executed while holding DB/table metadata locks during analysis, amplifying lock contention and planning latency under slow or remote storage.

What I'm doing:

• acquire the target table read lock only when pushDownSchemaFunc runs
• reload the session-aware target table under lock to copy its latest schema
• keep files() initialization and other analyzer logic outside the metadata lock

Fixes #issue

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• 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:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 4.0
  • 3.5
  • 3.4
  • 3.3

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Note

Moves schema pushdown locking into a short-lived table READ lock and simplifies Insert analysis flow outside locks.

• Analyzer (InsertAnalyzer):
  • Simplifies analyzeWithDeferredLock: performs properties analysis, files() schema pushdown, and query analysis without holding planner/meta locks; removes conditional lock-taking logic.
  • Updates files() schema pushdown to lock only the target table during schema copy:
    • Resolves Database and target table ID; within pushDownSchemaFunc acquires Locker READ lock on the table, reloads session-aware table, applies column mapping, then unlocks.
  • Keeps Hive connector metadata cache toggle based on source tables.
• Locking:
  • Introduces Locker/LockType usage to replace broader planner/meta lock during files() schema inference.

^{Written by Cursor Bugbot for commit d102414. This will update automatically on new commits. Configure here.}

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This is an automatic backport of pull request #63796 done by [Mergify](https://mergify.com).

[mergify]

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