Remove the unused variables and @deprecated function in Color Inversion quick settings

- SlashState is not used anymore
- composeChangeAnnouncement is @deprecated function and not used anymore
- Unused variables

Bug: 211937943
Test: manually test color inversion quick settings tile actions
Test: atest SystemUITests
Change-Id: I4c235d1e80993d712f2895e8fa1ea0dcfe01d7e9