fix(android) disables windows preview

Avoid white flash when starting the app.

Fixes: https://github.com/jitsi/jitsi-meet/issues/8237

android/app/src/main/res/values/styles.xml

@@ -3,5 +3,6 @@
     <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
         <!-- Customize your theme here. -->
         <item name="android:navigationBarColor">@color/colorPrimaryDark</item>
-    </style>
+        <item name="android:windowDisablePreview">true</item>
+   </style>
 </resources>