Set min_sdk_version to be part of mainline modules

Modules contributing mainline modules (APK/APEX) should set
min_sdk_version as well as apex_available.

For now setting min_sdk_version doesn't change build outputs.
But build-time checks will be added soon.

Exempt-From-Owner-Approval: cherry-pick from AOSP

Bug: 152655956
Test: m
Merged-In: If0e74debd5ef48011b5a4c6895410c5cee8f1eb3
Change-Id: If0e74debd5ef48011b5a4c6895410c5cee8f1eb3
(cherry picked from commit b60248fb2459a883b2a2a06eb9b2a43716e30adc)
diff --git a/Android.bp b/Android.bp
index 234b690..2aa5844 100644
--- a/Android.bp
+++ b/Android.bp
@@ -44,4 +44,5 @@
         enabled: true,
     },
     double_loadable: true,
+    min_sdk_version: "29",
 }