Remove all usage of deprecated code

[provokateurin]

No description provided.

[come-nc]

Did you test the events in the app to check that they are correctly firing and listened to like before?

[provokateurin]

Hehe this even fixes #1932 as the old event just wasn't fired anymore it seems.

[provokateurin]

Did you test the events in the app to check that they are correctly firing and listened to like before?

Yes, everything working as expected and for the group deletion event it also fixes a bug :)

[provokateurin]

/backport 05c6bcd to stable30

[provokateurin]

/backport 05c6bcd to stable29

[provokateurin]

/backport 05c6bcd to stable28

[backportbot]

The backport to stable28 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable28
git pull origin stable28

# Create the new backport branch
git checkout -b backport/3250/stable28

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 05c6bcd2

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/3250/stable28

Error: No changes found in backport branch

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.