Add a new method to set state description

- This CL add a new method setSeekBarStateDescription() to set
  the state of seek bar. Because in some case the description of
  seek bar is not align progress of seek bar.
- Add test case

Bug: 157629483
Test: make -j42 RunSettingsRoboTests
Change-Id: I432e6f9deef59756b0a41244d50aaada1ddac6a9