Upload: Add a MIME type exception for .docx generated by Google Docs.

This changeset adds an exception to prevent permission issues on `.docx` generated by Google Docs. This is a temporary fix for an upstream bug on the `finfo_file()` 
PHP function which returns a redundant MIME type for these documents.

Props winterstreet, jakariaistauk, mujuonly, mi5t4n, annashopina, audrasjb, azaozz, mikeschroder, oglekler.
Fixes #57898.




Built from https://develop.svn.wordpress.org/trunk@56497


git-svn-id: http://core.svn.wordpress.org/trunk@56009 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -3150,6 +3150,11 @@ function wp_check_filetype_and_ext( $file, $filename, $mimes = null ) {
 		$real_mime = finfo_file( $finfo, $file );
 		finfo_close( $finfo );
 
+		// finfo_file() returns redudant mime type for Google docs, see #57898.
+		if ( 'application/vnd.openxmlformats-officedocument.wordprocessingml.documentapplication/vnd.openxmlformats-officedocument.wordprocessingml.document' === $real_mime ) {
+			$real_mime = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
+		}
+
 		// fileinfo often misidentifies obscure files as one of these types.
 		$nonspecific_types = array(
 			'application/octet-stream',