Editing scheduling of future events: error explanations are missing, when overlapping issue occurs (5.0.0)

[samuelinniger]

Describe the bug
When scheduling future events and creating an overlapping issue, the comprehensive explanation is missing, see screenshot.

To Reproduce
Steps to reproduce the behavior:

1. In the plugin settings, activate "Metadata of scheduled events editable --> Yes, with effective changes to event date and location"
2. Edit the scheduling data of an existing scheduled event, and create an overlapping error with another existing scheduled event.

Screenshots
Bug:

Expected behavior
As in Plugin Version 3.7.5:
The user stays on the same page, an error message is shown.
LangVariable 211 + information about the conflict causing metadata-entry and the already existing event.

Environment (please complete the following information):
ILIAS version: v7.11 2022-06-29
Plugin version: 5.0.0
Browser: Firefox
Opencast: 11.0.0.