fix: display error message on conflicting recipe name

[SethFalco]

Topic and Scope

When renaming a recipe, if the recipe name is already taken it throws it shows a modal with Unknown answer returned from server. See logs..

This should be handled the same way as creating a new recipe, using the dedicated error returned from RecipeExistsException.

Concerns/issues

N/A

Chores

On the side, I've also updated the command to run nextcloud-docker-dev. It now specifies the nextcloud service, as this what is the recommendation from their repository.

docker-compose up -d nextcloud

— https://github.com/juliushaertl/nextcloud-docker-dev/blob/master/bootstrap.sh#L124

Formal requirements

There are some formal requirements that should be satisfied. Please mark those by checking the corresponding box.

• I did check that the app can still be opened and does not throw any browser logs
• I created tests for newly added PHP code (check this if no PHP changes were made)
• I updated the OpenAPI specs and added an entry to the API changelog (check if API was not modified)
• I notified the matrix channel if I introduced an API change