Agenda: Submitters are not loaded until motions has been opened

[MSoeb]

Description: If the setting "Show motion submitters in the agenda" is activated, the submitters of motions should appear under a motion in the agenda listing. This doesn't happen until the user has opened the motions module. May ne an autopupdate is missing.

Agenda item view without opening motions first:

Agenda item view after opening motions first:

Reproduction:

1. open a meeting
2. open Settings > Agenda > activate the setting "Show motion submitters in the agenda"
3. open Motions > Create a motion and add it to the agenda
4. open Agenda. Submitter should now be visible under the motion title
5. Reload the Agenda page with Strg+Shift+R -> Submitter should be gone
6. open Motions > open Agenda > Submitter is visible again

What should happen:
By activating the setting "Show motion submitters in the agenda" the agenda should show the submitter without opening the motion module first.