shell: remove from system_executes_vendor_violators.

And grant explicit exemption from system_executes_vendor_violators
neverallow rules.

This does not change the policy, but is needed to test the violator
attribute for emptiness.

Bug: 72662597
Test: build sepolicy
Change-Id: Iba79bb42e1381b221fe0dc53470f62f8267a4791