citra_qt: minor retranslation fix

When you change the language when a game is running, the "Continue" action in the "Emulation" menu would become "Start". This commit fixes the issue by checking and setting it if it should be "Continue". It seems that this is the only place with this issue.

src/citra_qt/main.cpp

@@ -1416,6 +1416,9 @@ void GMainWindow::OnLanguageChanged(const QString& locale) {
     LoadTranslation();
     ui.retranslateUi(this);
     SetupUIStrings();
+
+    if (emulation_running)
+        ui.action_Start->setText(tr("Continue"));
 }
 
 void GMainWindow::SetupUIStrings() {