Stub out getConnectionOwnerUid for telephony tests

This function is already tested in CTS module HostsideVpnTests and
unit test module InetDiagSocketTest.

Fix test error:
frameworks/opt/telephony/tests/telephonytests/src/com/android/internal/telephony/mocks/ConnectivityServiceMock.java:66:
error: ConnectivityServiceMock is not abstract and does not override
abstract method getConnectionOwnerUid(ConnectionInfo) in
IConnectivityManager
public class ConnectivityServiceMock extends IConnectivityManager.Stub

Bug: 9496886
Bug: 109758967
Test: atest frameworks/opt/telephony/tests/telephonytests/src/com/android/internal/telephony/mocks/ConnectivityServiceMock.java
Change-Id: I1a3275cc3417a8786bd4f09142141c64287bde80