BUG: backend crashes if user is in a non existing edit mode

[haase-fabian]

Description

After removing a custom edit mode. Users who have still selected that mode can no longer login to the backend.

Steps to Reproduce

1. add a custom edit mode
2. change the edit mode to that custom edit mode with a user
3. remove that custom edit mode
4. relog with that user

Expected behavior

seeing the backend of the neos installation

Actual behavior

Basically the backend crashes right after logging in. blank space

1. TypeError: Cannot read properties of undefined (reading 'backgroundColor')
2. TypeError: Cannot read properties of undefined (reading 'isEditingMode')
3. uncaught at application TypeError: Cannot read properties of undefined (reading 'backgroundColor')

Affected Versions

Neos: 8.0.3 UI: 8.0.1

[haase-fabian]

A fallback to the inline edit mode in case the selected mode is not defined should be sufficient to solve this issue.