Fix isFeatureEnabled namespace and overload usage

From service-connectivity, NAMESPACE_TETHERING must be used, as
NAMESPACE_CONNECTIVITY is used for the NetworkStack module. Also the
isFeatureEnabled with module name must be used, otherwise the "android"
package version is queried instead of the tethering module version.

BpfNetMaps is using flag value 1 to workaround this issue.
flags in NsdService, AutomaticOnOffKeepaliveTracker, and ConnectivityFlags
were not pushed currently.
So, this change has no effect to devices.

Bug: 279108992
Test: TH
(cherry picked from https://android-review.googlesource.com/q/commit:278db58bf536551158e8082d3e7572650a908b05)
Merged-In: I2b4b6a13c048c20beef52b1f43b9e21aca0c637a
Change-Id: I2b4b6a13c048c20beef52b1f43b9e21aca0c637a

tests/unit/java/com/android/server/ConnectivityServiceTest.java

@@ -2076,12 +2076,12 @@ public class ConnectivityServiceTest {
         }
 
         @Override
-        public boolean isFeatureEnabled(Context context, String name, boolean defaultEnabled) {
+        public boolean isFeatureEnabled(Context context, String name) {
             switch (name) {
                 case ConnectivityFlags.NO_REMATCH_ALL_REQUESTS_ON_REGISTER:
                     return true;
                 default:
-                    return super.isFeatureEnabled(context, name, defaultEnabled);
+                    return super.isFeatureEnabled(context, name);
             }
         }