Remove WRITE_SETTINGS permission from Tethering APIs

As TetheringManager moves to a Public API, remove the weak
WRITE_SETTINGS permission and use TETHER_PRIVILEGED instead. System
callers can still aquire TETHER_PRIVILEGED, and public callers must be
Device Owner or Carrier App to bypass (to be done in a future CL)

Bug: 374400379
Test: atest TetheringTest TetheringServiceTest CtsTetheringTests
Change-Id: Ia192021ac48f9eb3f27cc8c412f17629ad16a587
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 5cf5528..4d173a5 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -63,6 +63,7 @@
     static_libs: [
         "androidx.annotation_annotation",
         "connectivity-net-module-utils-bpf",
+        "com.android.net.flags-aconfig-java",
         "modules-utils-build",
         "modules-utils-statemachine",
         "networkstack-client",