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.

Bug: 152655956
Test: m
Merged-In: Idaa4c3bf2dbd8c0090c1e6681f077e63b84e9b13
Change-Id: Idaa4c3bf2dbd8c0090c1e6681f077e63b84e9b13
(cherry picked from commit 1e5505de456840204f2bf9e86f671b0f557dd532)
diff --git a/Android.bp b/Android.bp
index 57b3c10..39fbbec 100644
--- a/Android.bp
+++ b/Android.bp
@@ -96,6 +96,7 @@
         "com.android.media.swcodec",
         "com.android.tethering",
     ],
+    min_sdk_version: "29",
 }
 
 // Only libhwbinder_benchmark needs to have pgo enabled. When all places