libbinder.vendor: remove activity manager AIDL

These can't be used to communicate with am via /dev/vndbinder, and
we can save a bit of resources by removing these from libbinder.vendor.

Bug: 183654927
Test: build only
Change-Id: Ie2a35186f2991fc4c3379c93c13b09f08e3a2bcf
1 file changed