android9/overlay: don't disable provision plugin
UT explicitly disable built-in "provision" plugin, intending to use "ubuntu_provision". SailfishOS's oFono doesn't have "ubuntu_provision". it has its own provision plugin, which simply use the name "provision" and replace oFono's built-in one at build-time. So we disabled that, and now we have no provisioning plugin.
Remove the provision plugin from the --noplugin list, so that we use SailfishOS's one.