Remove unused resource from TetherServiceTest

TetherService is no longer query resource by itself after ag/11524847.
That CL miss to remove unused getResources code.
Now remove unused resource in this change.

Bug: 146918263
Test: atest TetherServiceTest
Change-Id: I3b0da2672246997aee16b11576ce5ae9bfe596dc
1 file changed