Make sure we apply the same RO+disabled filter everywhere

should_include_flag() was updated to target "system_ext" too, but
we had the same logic in other places that weren't updated.

Make them all use should_include_flag().

Fix: 407027922
Test: Manual test locally with the local soong change that hits this problem
Test: Treehugger
Flag: EXEMPT bugfix
Change-Id: I757091e86636dc99be9361b4d1134aae7331c30b