Remove building the ANGLE APK from AOSP

Mark ANGLE as product-specific and remove building the APK. CuttleFish
will continue to build the ANGLE libraries directly.

Bug: b/187342779
Test: launch_cvd --restart_subprocesses=false --start_webrtc=true --gpu_mode=guest_swiftshader
Change-Id: I6cd379a11e0c198ad72636253f1a33f2d1fc798f