Degrade HDR displays that mirror any content to an SDR display into SDR

Some apps have poor compatibility with receiving SDR content that was
tonemapped from HDR in mirroring use-cases. So, we apply a policy in
SurfaceFlinger that detects mirroring, and disables HDR in mixed SDR/HDR
mirroring.

Bug: 443315364
Bug: 301142304
Bug: 441469394
Flag: com.android.graphics.surfaceflinger.flags.md_degrade_hdr
Test: courage
Test: projecting HDR content does not degrade other HDR displays
Test: mirroring HDR content on both external and virtual displays does
degrade HDR displays
Test: Screenrecord correctly degrades from HDR to SDR.
Test: Note that "HDR" includes both HDR UI from photos *and* HDR video
from youtube
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:7c5c508ee550bfd8f05c0fe6750dbfe10727076c
Merged-In: I196247b127d83d182e79e9704ff59d86a2977c1d
Change-Id: I196247b127d83d182e79e9704ff59d86a2977c1d