Github actions: Remove android-33-ext4 from build image

Github workflow image ubuntu-20.04 version 20230109.1 have added Android
SDK Platform android-33-ext4. Something, possible the gradle version
bundled with qt does not parse this correctly, and sets
androidCompileSdkVersion in android-build/gradle.properties to "ext4"
instead of expected "33". This commit is a quick fix to the problem, so
the build will revert to android-33 wich was used before 20230109.1.

.github/workflows/android_release.yml

@@ -63,6 +63,9 @@ jobs:
           ndk-version: r21e
           add-to-path: false
 
+      - name: Remove Android SDK android-33-ext4
+        run: ${ANDROID_SDK_ROOT}/cmdline-tools/latest/bin/sdkmanager --uninstall "platforms;android-33-ext4"
+
       - name: Install ccache
         run:  sudo apt-get install ccache