Deck: Description update activities are too verbose and HTML tags are displayed to users

[Valdnet]

Describe the bug
Incorrectly displayed content of the card description change in "Activity" for the user.

To Reproduce
Steps to reproduce the behavior:

1. Create a board.
2. Add stack.
3. Add card.
4. Add a card description.
5. Go to "Activity" Nextcloud.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots

Client details:

• OS: [e.g. iOS]
  Win10
• Browser [e.g. chrome, safari]
  Firefox
• Version [e.g. 22]
  73.0.1

Nextcloud version: (see Nextcloud admin page)
18.0.1

Deck version:
0.8.0

[juliushaertl]

Non-functional diff display was removed now with 54536eff93a4a8676deea27dc32744993f21db26