Add CtsTetheringUtils methods for wifi tethering without permission

Device Owner and Carrier-privileged tethering usage relies on starting
tethering without TETHER_PRIVILEGE permission. Add utilities to
CtsTetheringUtils to do this.

Bug: 295979433
Test: atest DeviceOwnerTest TetheringManagerTest
Change-Id: Id3eba71481e27ccfa32f2b0588b8a74c490c5311
1 file changed