[layout compilation] Modify sepolicy to allow installd to run viewcompiler

We will generate precompiled layouts as part of the package install or upgrade
process. This means installd needs to be able to invoke viewcompiler. This
change gives installd and viewcompiler the minimal set of permissions needed for
this to work.

Bug: 111895153
Test: manual
Change-Id: Ic1fe60bd264c497b5f79d9e1d77c2da4e092377b