lang_ensure_loaded(): load current plugin's strings

Move the code to load the currently active plugin's strings from
lang_get() to lang_ensure_loaded().

This is in preparation for fixing issue #21201, as this code would then
be duplicated in lang_get_defaulted().

core/lang_api.php

@@ -171,7 +171,8 @@ function lang_map_auto() {
 }
 
 /**
- * Ensures that a language file has been loaded
+ * Ensures that a language file has been loaded.
+ * Also load the currently active plugin's strings, if there is one.
  * @param string $p_lang The language name.
  * @return void
  */
@@ -181,6 +182,12 @@ function lang_ensure_loaded( $p_lang ) {
 	if( !isset( $g_lang_strings[$p_lang] ) ) {
 		lang_load( $p_lang );
 	}
+
+	# Load current plugin's strings
+	$t_plugin_current = plugin_get_current();
+	if( $t_plugin_current !== null ) {
+		lang_load( $p_lang, config_get_global( 'plugin_path' ) . $t_plugin_current . '/lang/' );
+	}
 }
 
 /**
@@ -293,14 +300,6 @@ function lang_get( $p_string, $p_lang = null ) {
 	if( lang_exists( $p_string, $t_lang ) ) {
 		return $g_lang_strings[$t_lang][$p_string];
 	} else {
-		$t_plugin_current = plugin_get_current();
-		if( !is_null( $t_plugin_current ) ) {
-			lang_load( $t_lang, config_get_global( 'plugin_path' ) . $t_plugin_current . DIRECTORY_SEPARATOR . 'lang' . DIRECTORY_SEPARATOR );
-			if( lang_exists( $p_string, $t_lang ) ) {
-				return $g_lang_strings[$t_lang][$p_string];
-			}
-		}
-
 		if( $t_lang == 'english' ) {
 			error_parameters( $p_string );
 			trigger_error( ERROR_LANG_STRING_NOT_FOUND, WARNING );