Enable optimizer on service-connectivity

The optimizer has been enabled in downstream branches (including those
used for upcoming module releases) for a few months. This brings aosp in
line with them.

This is a cherry-pick of change:
I3be9422a431a5b5bc1478960ce332a89377bd632

where proguard.flags have been replaced with the most up-to-date version
used in downstream branches.

Test: m
Merged-In: I3be9422a431a5b5bc1478960ce332a89377bd632
Change-Id: I55455eb58d3fdc4dbf3ea81961d5c7756fea0046
diff --git a/service/Android.bp b/service/Android.bp
index 25b970a..7dbdc92 100644
--- a/service/Android.bp
+++ b/service/Android.bp
@@ -216,6 +216,11 @@
     apex_available: [
         "com.android.tethering",
     ],
+    optimize: {
+        enabled: true,
+        shrink: true,
+        proguard_flags_files: ["proguard.flags"],
+    },
     lint: { strict_updatability_linting: true },
 }