Inject commit hash into AC build.gradle files at buildtime

context

• In a3a5306f, we added a patch to the android-components build process that prevents gradle from invoking git rev-parse to obtain the current build's commit hash (because git is absent in our build containers and invoking it will abort the build), instead simply inserting the dummy string "release build" where the hash would have occured
• However, having the git hash in build artifacts can be quite useful for debugging later, so we'd like to preserve it, if we can.

changes

• Inject the commit hash into the android-components build.gradle files using sed and c("abbrev") as we do in the fenix build process in 5912606f