Comments: When a comment is submitted, ensure the `user_ID` element in the...

Comments: When a comment is submitted, ensure the `user_ID` element in the array that's passed to the `preprocess_comment` filter gets populated.

Fixes #34997

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git-svn-id: https://core.svn.wordpress.org/trunk@36003 1a063a9b-81f0-0310-95a4-ce76da25c4cd