Switch to -nodeps flavor of mockito-kotlin

This allows use of mockito-kotlin without pulling in
a specific implementation of Mockito.

Unfortunately there are currently multiple versions of
Mockito in use, including single-target prebuilts which
also include mockmaker plugin metadata.

Since mocktio-kotlin is a small library which depends
only on the stable Mockito API (as wrapper functions),
it can be used along with multiple versions without
explicitly defining a runtime dependency.

Bug: 339853443
Test: Treehugger presubmit
Flag: TEST_ONLY
Change-Id: I4431c1a8438c7a02d051fb5965f065dfbbd70102