Reduce polling interval / background activity for rich workspaces

[juliushaertl]

We likely don't need to fetch rich workspace details as often as with a regular document

[juliushaertl]

We should especially improve this if:

• The viewer app is open
• The rich workspace is scrolled out of view
• The window is in the background

Considering we solved #4943 we can probably think about just disconnecting the workspace in the background.