Extend timeout for requesting tethered interface

Extend the timeout to lower the EthernetTetheringTest flaky.

Besides, also explicitly exempt entitlement check in
EtetherntTetheringTest because it do not test tethering upstream
currently. Thus, the tests would not be interrupted by entitlement
check if test SIM is entitlement required.

Bug: 156713866
Test: TetheringCoverageTests, CtsTehteringTest

Change-Id: I45e8e8d737486def9d0de8943ec7f09ca0942a0b