This slider is temporary and will be replaced by the final UI in the next couple weeks.
In this first version, the slider is added in Settings -> Accessibility -> Color and motion. It is discrete with three values.
The slider manipulates the setting currently named CONTRAST_LEVEL in Settings.Secure. This setting is ranging from [-1, 1] with a default value of 0. However, the three values of the slider correspond to the contrast values [0, 0.5, 1] respectively
Test: Manual: put a log before Settings.System.putFloatForUser, move the slider manually and verify the logs
Test: make RunSettingsRoboTests ROBOTEST_FILTER=ContrastLevelSeekBar
Bug: 259091608
Change-Id: I2eaf751d6008ad20b3564dde2c0f4648cc6c8178
