Updates to SlopController

- Addressed comments in ag/23670464
- Moved the creation of the controller from the rotary input mapper
  constructor, to its `populateDeviceInfo`, since the slop params were
  not being read in the constructor (since the device property map is
  not initialized when the input mapper is created).
- Added logs to note the slop params

Bug: 285957835
Test: atest SlopControllerTest

Change-Id: Id1bd77b52c9d93d30d3d2594662e19ccc40a1bb6