Add max column config and session properties to equality delete as jo…

[tdcmeehan]

…in optimizer

Description

Adds session and config properties to the Iceberg connector allowing users to toggle the Iceberg delete-as-optimize rule based on the column count of the delete file. Deprecates the old binary flag, in the future it will be deleted and replaced with the column count toggle.

Motivation and Context

Fixes #25455 by introducing an upper bound to the number of columns allowed to use this optimization.

Impact

Fix #25455

Test Plan

Added unit tests demonstrating the toggling of the optimization.

Contributor checklist

• Please make sure your submission complies with our contributing guide, in particular code style and commit standards.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
• If release notes are required, they follow the release notes guidelines.
• Adequate tests were added if applicable.
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Release Notes

Please follow release notes guidelines and fill in the release notes below.

  == RELEASE NOTES ==

  Iceberg Connector Changes
  * Add ``iceberg.delete-as-join-rewrite-max-delete-columns`` configuration property and ``delete_as_join_rewrite_max_delete_columns`` session property to control when equality
  delete as join optimization is applied. The optimization is now only applied when the number of equality delete columns is less than or equal to this threshold (default: 400).
  Setting this to 0 disables the optimization. See :doc:`/connector/iceberg` for details.
  * Deprecate ``iceberg.delete-as-join-rewrite-enabled`` configuration property and ``delete_as_join_rewrite_enabled`` session property. Use
  ``iceberg.delete-as-join-rewrite-max-delete-columns`` instead.

[steveburnett]

Formatting suggestions. The text itself reads fine, no concern with the content.

[tdcmeehan]

Thanks @steveburnett, I've incorporated your suggestions!

[hantangwangd]

Thanks for this change, lgtm overall. Just some little nits.

[steveburnett]

LGTM! (docs)

Pull updated branch, new local doc build. Looks good, thanks!

[hantangwangd]

Thanks for the fix, lgtm!