Fix lunch choices for git_main

We add "trunk_staging-" for all COMMON_LUNCH_CHOICES so they are
valid in the trunk stable setup.

Bug: 307738446
Test: lunch
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:e36683f026781d75008cbf9794f6a614c254f6d1)
Merged-In: I1492ec879e2131fbe5c7110573fd932712251a31
Change-Id: I1492ec879e2131fbe5c7110573fd932712251a31
1 file changed