Add dispatcher module for Hilt injection (2/3)

Make Injector injectable so the existing dependencies can be access by the new classes via injecting Injector, and the existing classes can use the new class via Injector by injecting new classes into Injector.
Inject dispatchers for both world.

Bug: 288128417
Test: launch picker

Change-Id: I05d7db38891fd5320d3efc857499e3774d8da7db