Use SettingsShim to hide different implementation in shim

TetheringService call different Settings API to check write settings
permission between R and S.

Bug: 182211575
Test: install S module to R device and both run mts tests build with S
and R.

Ignore-AOSP-First: to address the conflict
Change-Id: I3e7f6525e9776992bd96b17c132b749b12285bbd
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 89f1505..3ca340f 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -40,6 +40,7 @@
         "net-utils-framework-common",
         "net-utils-device-common",
         "netd-client",
+        "NetworkStackApiCurrentShims",
     ],
     libs: [
         "framework-connectivity",