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
Change-Id: I1492ec879e2131fbe5c7110573fd932712251a31
diff --git a/AndroidProducts.mk b/AndroidProducts.mk
index 1f24376..3e7e641 100644
--- a/AndroidProducts.mk
+++ b/AndroidProducts.mk
@@ -3,6 +3,6 @@
     $(LOCAL_DIR)/poplar.mk
 
 COMMON_LUNCH_CHOICES := \
-    poplar-eng \
-    poplar-user \
-    poplar-userdebug
+    poplar-trunk_staging-eng \
+    poplar-trunk_staging-user \
+    poplar-trunk_staging-userdebug