Behavior of already connected components during reassignment

[janniclas]

As @johannesduesing mentioned: "The only issue i can see is that you are currently able to re-assign a component to the same instance that it is already using, which is actually triggering a re-assignment call to the registry. I would expect to either hide the currently used dependency or just give the user a message that re-assignment is not needed because the desired dependency is already established.
Since i remember talking with @janniclas about this i'm not sure if that's intended behaviour for this PR, so i will still approve it in the current state."
The question is how we want to handle this.

1. We could hide the connected components, but I thought it might be interesting for the admin to see the currently active connections during reconnect mode.
2. We can display an extra notification when trying to reconnect two already connected components (maybe the reassignment is wanted in some cases).