androiddeployqt does not sign Android App Bundles

When calling androiddeployqt with the --aab option (new in 5.14, see QTBUG-68202) and signing parameters, only the resulting APK is signed but the AAB is unsigned. This prevents uploading the AAB to Google Play.

Steps to reproduce

1. Build Android app
2. Run e.g.

   androiddeployqt --aab --release --sign my.keystore --storepass mypass --input project-deployment-settings.json- -output android-build- -android-platform android-28- -jdk path/to/JDK

3. Run

   jarsigner --verify path/to/android-build.aab

Expected results

jarsigner says that the AAB is signed.

Actual results

jarsigner outputs:

no manifest.

jar is unsigned.