surfaceflinger: minor dumpsys improvements

In the order of importance,

 - fix eglGetConfigAttrib calls
 - mark Zs as relative in minidump
 - dump DisplayDevice wide color states
 - rename pixelformat to defaultPixelFormat in layer state
 - better grouping and indentation for DisplayDevice dump

Bug: 76415976
Test: dumpsys
Change-Id: If9254ffe43cb1de82d562fcc27e828d54eba9387