getDisplayDecorationSupport: return more detailed info

Call the updated native version of getDisplayDecorationSupport (added in
I961051c0a660b596039ac04b546040764ee20d34), and convert the NDK struct
into a Java class. Depend on the graphics AIDLs, which now have Java
backends. A future CL will update SysUI to call the new API.

Add a PixelFormat for R_8 to correspond to the native version. This will
allow SysUI to use COLOR_MODE_A8 when the HAL reports R_8.

If64fd6924960f592b7a211371bc2ca6536ae34f7 demonstrates using this.

Bug: 216644902
Test: manual
Change-Id: I0e34c6d6e369fda0a96231ab38c3bd5f3bfe3e06