Add feature flag, and support for new secure settings in framework

The secure setting is only updated and guarded with feature flag.
Reason for single update rather than 2 separate API to update level vs
mode : In Daltonizer.cpp either of the change requires re-calculation of
all matrices (current implementation). We can optimize further later
once we have basic functionality implemented and working.

Test: Locally tested
Bug: 322829049
Flag: com.android.server.accessibility.enable_color_correction_saturation

Change-Id: Ic919c7f01ce4723ecf933b7bdc25a530e372f5ae