[BugFix] Cast COALESCE children to common type in JOIN USING transformer (backport #72338)

[mergify]

Why I'm doing:

createCoalesceOperator resolved a common result type for the synthesized USING-projection COALESCE but passed the original left/right operands as children without casting, so the call's actual child types could disagree with the resolved function signature (e.g. DATETIME child under a coalesce(VARCHAR) signature). Wrap children whose type differs from the common type in an implicit CAST and look up the function with {commonType, commonType} so the signature is consistent.

What I'm doing:

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 pr needs auto generate documentation
• 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
  • 4.1
  • 4.0
  • 3.5
  • 3.4

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This is an automatic backport of pull request #72338 done by [Mergify](https://mergify.com).

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