Link to Briefcase in Android documentation is a redirect

[freakboy3742]

Documentation

In the Android documentation, there is a link to Briefcase that points to the older readthedocs.io URL, rather than the newer, canonical beeware.org site.

Linked PRs

• gh-148779: Update Briefcase link in android.rst documentation #148777
• [3.14] gh-148779: Update Briefcase link in android.rst documentation (GH-148777) #148780
• [3.13] gh-148779: Update Briefcase link in android.rst documentation (GH-148777) #148781