Small change to preview email input feature

Set email to `user.email` only if it was not touched by the user first

Signed-off-by: Alexander Schreiner <github@alexander-schreiner.de>

src/features/emails/components/EmailEditor/EmailSettings/PreviewTab.tsx

@@ -23,7 +23,11 @@ const PreviewTab: FC = () => {
   const { emailWasSent, isLoading, reset, sendTestEmail } = useSendTestEmail();
   const [emailError, setEmailError] = useState(false);
   const [destinationEmailAddress, setDestinationEmailAddress] = useState('');
-  useEffect(() => setDestinationEmailAddress(user?.email ?? ''), [user?.email]);
+  useEffect(() => {
+    if (user && destinationEmailAddress === '') {
+      setDestinationEmailAddress(user.email);
+    }
+  }, [user?.email]);
 
   if (!user) {
     return null;