Revert "Add PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT"

Revert "Add system_ext_userdebug_plat_sepolicy.cil for GSI"

Revert submission 1824717-gsi_debug_policy

Reason for revert: Breaks the build (see b/200933187).
Reverted Changes:
I37ef02628:Add a copy of debug policy to GSI system image
I9c3dad8bb:Add PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT
I43adc6ada:Add system_ext_userdebug_plat_sepolicy.cil for GSI...
I4d6235c73:Add /system_ext/etc/selinux/ to the debug policy s...
Bug: 200933187
Change-Id: I4252793fbee1b83e3db26f944ac0be6581fa773f