Android: Include the resConfigs so that the package can be uploaded

The Google Play Store requires the resConfigs to be set to something
valid otherwise it will not accept the package, so we default it to "en"
to ensure it is valid.

Fixes: QTBUG-81735
Change-Id: I1180481a1e5b88057aed2417716ca4d334080c00
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

src/android/templates/build.gradle

@@ -59,4 +59,8 @@ android {
     aaptOptions {
         noCompress 'rcc'
     }
+
+    defaultConfig {
+        resConfigs "en"
+    }
 }