Fix TelephonyManagerTests

Disable check for getSystemSelectionChannels since it's not functional
until S QPR.
Increase reboot timeout since state can still be unavailable after 15
seconds.

Test: atest TelephonyManagerTest
Bug: 189188063
Change-Id: I44e31e3866c5e44f88cb8e7df6981124039ef864
1 file changed