I think this is the same as comment https://github.com/mozilla-b2g/gaia/pull/19769#discussion_r13223157 , using a 'pick' activity let me retrieve a `mozContact` as well, so this seems not to be a security issue.

The goal is to know if at least there is one app which offers the activity, trying to not hardcode anything but the 'activity name', which is well know by the App (because actually we know which activity we need to launch :) ).