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
Change-Id: I2b4b6a13c048c20beef52b1f43b9e21aca0c637a
6 files changed