Login and registration: Add a filter to allow to disable the Login screen language dropdown.

This change introduces the `display_login_language_dropdown` filter which allows to disable the Login screen language dropdown. 

Follow-up to [52058].

Props rickcurran, audrasjb, ocean90, hellofromtonya, costdev, johnbillion.
Fixes #54675.

Built from https://develop.svn.wordpress.org/trunk@52404


git-svn-id: http://core.svn.wordpress.org/trunk@51996 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-beta3-52403';
+$wp_version = '5.9-beta3-52404';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.

wp-login.php

@@ -312,11 +312,21 @@ function login_footer( $input_id = '' ) {
 	</div><?php // End of <div id="login">. ?>
 
 	<?php
+	if (
+		! $interim_login &&
+		/**
+		 * Filters the Languages select input activation on the login screen.
+		 *
+		 * @since 5.9.0
+		 *
+		 * @param bool Whether to display the Languages select input on the login screen.
+		 */
+		apply_filters( 'display_login_language_dropdown', true )
+	) {
 		$languages = get_available_languages();
 
-	if ( ! empty( $languages ) && ! $interim_login ) {
+		if ( ! empty( $languages ) ) {
 			?>
-
 			<div class="language-switcher">
 				<form id="language-switcher" action="" method="get">
 	
@@ -361,9 +371,8 @@ function login_footer( $input_id = '' ) {
 	
 					</form>
 				</div>
-
 		<?php } ?>
-
+	<?php } ?>
 	<?php
 
 	if ( ! empty( $input_id ) ) {