fix(ubuntu): specify all avd-related environment variables

[mikehardy]

This action does simply define all of the standard env vars per the android documentation https://developer.android.com/tools/variables#envar

Additionally, it forcibly overwrites those variables though there may be valid reasons that they exist already:

1- for self-hosted runners people may define the variables so the large AVD files are in a non-standard location 2- for ubuntu-24 with XDG_CONFIG_HOME set (vs ubuntu-22) one of the variables was already set, but to an unexpected location. You can either clobber it and install (which works) or you can take it and use it (which was also a valid workaround)

This PR attempts to respect the variables if they exist, but make sure they are all set + directories are created either way

Osoletes #405

[mikehardy]

@ychescale9 I updated this PR to match current main and edited the description to justify why I think it is worthwhile Fine if you disagree - we can just close it then - but wanted to at least post it once current + clean in case it could go in Cheers