Revert "Add permission check for blurs in SurfaceFlinger"

Revert "Remove public usages of FLAG_BLUR_BEHIND"

Revert "Add pid and uid to SF::setClientStateLocked"

Revert "Add USE_BACKGROUND_BLUR to cts expected permissions"

Revert submission 13350963-blur_system_api

Reason for revert: This topic made blurs a system api. API council voted against that and we will instead aim to make it public for S. None of these changes are relevant in that case.

Reverted Changes:
I3683db296:Remove public usages of FLAG_BLUR_BEHIND
I23b21b603:Add USE_BACKGROUND_BLUR to cts expected permission...
Id21f03793:Add pid and uid to SF::setClientStateLocked
If5d8344a5:Add permission for blur SystemApi
I70d1e1715:Add permission check for blurs in SurfaceFlinger
Icf98c3607:Make window background blurs SystemApi
I0b881ec6e:Make BackgroundBlurDrawable a SystemApi

Bug: 177523043
Test: m
Change-Id: I4645b0483df69f4e5e970835fb3a232eb89c8f06
Merged-In: I4645b0483df69f4e5e970835fb3a232eb89c8f06