I18N: Check that $wp_locale global is set before calling its methods.

This avoids a fatal error if these functions are called in a mu-plugin before `$wp_locale` is set:
* `wp_get_list_item_separator()`
* `wp_get_word_count_type()`

Follow-up to [52929], [52933], [55279], [55295].

Props kraftbj.
Fixes #56698.
Built from https://develop.svn.wordpress.org/trunk@55351


git-svn-id: http://core.svn.wordpress.org/trunk@54884 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.2-beta2-55350';
+$wp_version = '6.2-beta2-55351';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.