fix: Dialog using wrong Navigator

lib/utils/event_extension.dart

@@ -10,7 +10,7 @@ extension LocalizedBody on Event {
   void openFile(BuildContext context, {bool downloadOnly = false}) async {
     if (!downloadOnly &&
         [MessageTypes.Image, MessageTypes.Sticker].contains(messageType)) {
-      await Navigator.of(context).push(
+      await Navigator.of(context, rootNavigator: false).push(
         MaterialPageRoute(builder: (_) => ImageView(this)),
       );
       return;

lib/utils/platform_infos.dart

@@ -43,6 +43,7 @@ abstract class PlatformInfos {
     var version = await PlatformInfos.getVersion();
     showAboutDialog(
       context: context,
+      useRootNavigator: false,
       children: [
         Text('Version: $version'),
         RaisedButton(

lib/utils/url_launcher.dart

@@ -73,6 +73,7 @@ class UrlLauncher {
         if (await showOkCancelAlertDialog(
               context: context,
               title: 'Join room $roomIdOrAlias',
+              useRootNavigator: false,
             ) ==
             OkCancelResult.ok) {
           roomId = roomIdOrAlias;
@@ -116,6 +117,7 @@ class UrlLauncher {
       if (await showOkCancelAlertDialog(
             context: context,
             title: 'Message user ${user.id}',
+            useRootNavigator: false,
           ) ==
           OkCancelResult.ok) {
         roomId = (await showFutureLoadingDialog(