Add a dependency object in TetheringConfiguration

Address a TODO in TetheringConfiguration to use a dependency object
instead of static mocking on DeviceConfig.

This avoids TetheringConfiguration dependencies on internal
implementation of DeviceConfigUtils, unblocking changes in
DeviceConfigUtils.

Bug: 279108992
Test: atest TetheringTests
(cherry picked from https://android-review.googlesource.com/q/commit:6d38c018523688004b3d43e6794bec5eba8aee03)
Merged-In: I252eaadff85fa47b894e989b4f2527b00c5dca56
Change-Id: I252eaadff85fa47b894e989b4f2527b00c5dca56
3 files changed