Add android sdk tools to android sdk module.

This android tools are required for flutter doctor to find and report
licenses approval.

Change-Id: I199c801e2daef501bc329b129e13ea37e5051ae0
Bug: https://github.com/flutter/flutter/issues/62811`
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/5020
Reviewed-by: Tong Wu <wutong@google.com>
Commit-Queue: Godofredo Contreras <godofredoc@google.com>