Motion > Amendments: deletion of bullet point/paragraphs is not recognized as change

[MSoeb]

Describe the bug
If a bullet point or paragraph is completely deleted with a new amendment, this deletion is not recognized as an amendment. After saving, it is displayed that no change has been made. The crucial point is, that amendment which are created in this way show have no changed content and therefor the information of the change is not available anymore.

Here an example for bullet points.

original motion content:

view of bullet point before editing:

view of bullet point after edit:

amendment view after save:

How to Reproduce
Steps to reproduce the behavior:

1. open a meeting
2. open motions > create a motion with one paragraph and three bullet points
3. create amendment to the second bullet point and delete the whole content > save
4. Amendment is now empty.

Expected behavior
If an amendment deletes a bullet point or a paragraph completely, the amendment should be displayed correctly. Specifically, this means that the bullet point or the paragraph is crossed out in red.

This is part of the Meta diff Issue #2956

[MSoeb]

Changes:

• extended to paragraphs
• added high label

[emanuelschuetze]

I found the problematic pr which caused the error:
#3667

With commit dc4d970 the reported error was introduced.