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:9320904856b93682e5cf52cafa59037940431688)
Merged-In: Iae9d3de2ee9b5ca7b15c4b78abc548ea434e575e
Change-Id: Iae9d3de2ee9b5ca7b15c4b78abc548ea434e575e
1 file changed