Fix garbled text in editor toasters

(cherry picked from commit 3006394a69af7ffdf8770cb28b65a690ebfdae00)

editor/gui/editor_toaster.cpp

@@ -147,7 +147,7 @@ void EditorToaster::_notification(int p_what) {
 void EditorToaster::_error_handler(void *p_self, const char *p_func, const char *p_file, int p_line, const char *p_error, const char *p_errorexp, bool p_editor_notify, ErrorHandlerType p_type) {
 	// This may be called from a thread. Since we will deal with non-thread-safe elements,
 	// we have to put it in the queue for safety.
-	callable_mp_static(&EditorToaster::_error_handler_impl).bind(p_file, p_line, p_error, p_errorexp, p_editor_notify, p_type).call_deferred();
+	callable_mp_static(&EditorToaster::_error_handler_impl).bind(String::utf8(p_file), p_line, String::utf8(p_error), String::utf8(p_errorexp), p_editor_notify, p_type).call_deferred();
 }
 
 void EditorToaster::_error_handler_impl(const String &p_file, int p_line, const String &p_error, const String &p_errorexp, bool p_editor_notify, int p_type) {