Tests: Set the current user to Editor in `test_utf8mb3_post_saves_with_emoji()`.

This avoids a "Sorry, you are not allowed to edit this post" error further in the test. The test is currently skipped on GitHub Actions, as only runs on older MySQL versions specifically with the `utf8` character set.

The user was previously set for all tests in the file in the `set_up()` method, however that is no longer the case, as it was not required for the majority of the tests. It is, however, necessary for the `edit_post()` call in this particular test.

Follow-up to [30346], [53785].

See #55652.
Built from https://develop.svn.wordpress.org/trunk@54067


git-svn-id: http://core.svn.wordpress.org/trunk@53626 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-54066';
+$wp_version = '6.1-alpha-54067';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.