DEV - Improve error handling for notifications module

[prooflesben]

User Story

As a dev I want to have more error handling so that when something goes wrong in the backend I can diagnose the problem easily.

Overview

The main task of this ticket is to improve our error handling in the backend and on our routes. We have a lot of aws things in our backend and no idea to know if we made a logistic code mistake or if there was an aws error or what type of error occurred.

Tasks

• Go through each notifications module service method and improve error handling.
• Update the swagger docs so that the new error handling matches each status code.
  • This shouldn't change too much since a lot of the new error handling should just be in the 400 or 500 category and we just have those say {Error occurred} in the swagger docs
• Update test to make sure they pass and include the new error thrown in each service method.

Acceptance Criteria

• Updated error handling for each service method.
• Updated Swagger UI for the notifications module.
• Updated unit test.