[Mediacontroller] Added refreshing the list of handles

[Mediacontroller] Added refreshing the list of handles

[Bug] If native application (e.g. service) adds the playlist,
web api is able to gather it, but cannot perform any actions on it,
because web API stores only handles to playlists created by itself.

[Solution] Added functionality of refreshing handles always when gathering
a playlists handles using native API

[Verification] Code compiles without errors.

Change-Id: I9bb757f50c3bc4167b0a97c923d49a1ccbbe0195