Feedback: Always encode the URI properly

Encoding the URI may work on Android, but it's safter to always just
encode it, specially if we ever add a '&' in the body.

lib/widgets/app_drawer.dart

@@ -95,10 +95,10 @@ class AppDrawer extends StatelessWidget {
               var subject = 'GitJournal Feedback';
               var body =
                   "Hey!\n\nHere are some ways to improve GitJournal - \n \n\nVersion: $versionText\nPlatform: $platform";
-              if (Platform.isIOS) {
+
               subject = Uri.encodeComponent(subject);
               body = Uri.encodeComponent(body);
-              }
+
               var url = 'mailto:$emailAddress?subject=$subject&body=$body';
               launch(url);