Bump Android SDK Commandline Tools from 9.0 to 12.0

[rmartin16]

Changes

• Requires Android Commandline Tools 12.0
• Whether using Briefcase's SDK install or a user-managed one, version 12.0 will just be installed if it isn't already

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[rmartin16]

well....ever keeping us on our toes....Google's AVD manager in cmdline-tools v12.0 apparently respects XDG_CONFIG_HOME. So, the AVD config is in ~/.config/.android/avd instead of ~/.android/avd now....and Briefcase can't find the AVD's config to update it...

[rmartin16]

FWIW, Android Studio will also respect XDG_CONFIG_HOME when creating an AVD.

However, $BRIEFCASE_HOME/tools/android_sdk/emulator/emulator will not be able to find this AVD that was just created in $XDG_CONFIG_HOME/.android.....because (surprise surprise) it doesn't respect XDG_CONFIG_HOME.

The avdmanager does support a -p/--path to define "the location where the directory for this AVD's files will be created".....but it still puts the AVD's ini file in $XDG_CONFIG_HOME/.android (!!!!!!) and we still have the same issue.

So, anyway....I think it'll be best to ensure XDG_CONFIG_HOME is always overridden when running avdmanager...

[rmartin16]

hmm...another PytestUnraisableExceptionWarning...although transient: https://github.com/beeware/briefcase/actions/runs/9005657139/job/24741533654?pr=1778

[freakboy3742]

LGTM