Improve error handling on the flask backend

[jayantbh]

Description:

Right now errors from the flask backend are often returned as HTML errors instead of a more system parseable JSON style error.

We should change that such that flash returns errors as JSON instead.
https://flask.palletsprojects.com/en/2.3.x/errorhandling/

[dominicghizzoni]

could you assign this to me?

[jayantbh]

Sure, @dominicghizzoni

[larrikin-coder]

is te issue still open @dominicghizzoni ? If it is please assign me this issue.

[dominicghizzoni]

is te issue still open @dominicghizzoni ? If it is please assign me this issue.

yes you may continue my work on it

[jayantbh]

@larrikin-coder, there's an existing PR for it, #567
You may decide to continue on that (or look at the review already done on that) as a starting point.

[joshh35]

@jayantbh Is this issue still open to contribute