Conditionally disable TetheringApiCurrentLib

The "current" targets are only necessary in branches that can use
non-stable APIs, and can fail to build otherwise.

Apply ConnectivityNextEnableDefaults so they are disabled on such
branches. Also deprecate NetworkStackNextEnableDefaults, so
ConnectivityNextEnableDefaults is used everywhere.

Bug: 190249673
Test: m
Change-Id: I1b152f3cc22f1bed6444d280f0066e480980e949
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 041a3ae..0e04dbe 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -64,6 +64,7 @@
 android_library {
     name: "TetheringApiCurrentLib",
     defaults: [
+        "ConnectivityNextEnableDefaults",
         "TetheringAndroidLibraryDefaults",
         "TetheringApiLevel"
     ],
@@ -158,7 +159,7 @@
 // Non-updatable tethering running in the system server process for devices not using the module
 android_app {
     name: "InProcessTethering",
-    defaults: ["TetheringAppDefaults", "TetheringApiLevel"],
+    defaults: ["TetheringAppDefaults", "TetheringApiLevel", "ConnectivityNextEnableDefaults"],
     static_libs: ["TetheringApiCurrentLib"],
     certificate: "platform",
     manifest: "AndroidManifest_InProcess.xml",