Tests: Ensure prerequisites are met for draft length tests in Tests_L10n.

These three tests for `wp_dashboard_recent_drafts()` would run into a PHP 8.1 "passing null to non-nullable" deprecation for the call to `ltrim()` when the result of `get_edit_post_link()` is passed to `esc_url()`.

Setting a deprecation expectation would not solve this as the returned value would still not match the expected value(s).

The recent drafts list is only displayed on the Dashboard screen for users with the `edit_posts` capability. By setting the current user to Editor, the prerequisites for `wp_dashboard_recent_drafts()` are met, which means the deprecation notice is avoided and the assertions will succeed.

This commit addresses a few errors in the test suite along the lines of:
{{{
1) Tests_L10n::test_length_of_draft_should_be_counted_by_words
ltrim(): Passing null to parameter #1 ($string) of type string is deprecated

/var/www/src/wp-includes/formatting.php:4376
/var/www/src/wp-admin/includes/dashboard.php:657
/var/www/tests/phpunit/tests/l10n.php:449
/var/www/vendor/bin/phpunit:123
}}}

Follow-up to [45505], [52253], [52259].

Props jrf, desrosj, SergeyBiryukov.
See #56681, #55652, #55656.
Built from https://develop.svn.wordpress.org/trunk@54365


git-svn-id: http://core.svn.wordpress.org/trunk@53924 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-beta2-54364';
+$wp_version = '6.1-beta2-54365';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.