Description

As part of the CHE-167 Back End Error Handling Refactor story, this PR aims to:

• Refactor the protect auth middleware to make use of custom error classes
• Refactor the validate-session auth route and authController to use of the protect middleware
• Add the user field to express's Request interface to eliminate the need to define a CustomRequest type
• Delete our CustomRequest interface and any usage of it
• Refactor/simplify repeated usage of protect middleware in router files

Jira Task

JIRA TICKET

Testing Instructions

• run npm run docker-remove-all
• run npm run docker-build-check to ensure linting and tests pass
• run npm run docker-dev
• log in with test user and make sure app is working as expected

Checklist

All Team Members

• I added a descriptive title to this PR.
• I filled out the Description, Jira Task, and Testing Instructions sections above.
• I added or updated [Jest unit tests]for any changes to components, server-side controllers, etc.
• I ran npm run docker-build-check in my local environment to check that this PR passes all linting checks and unit tests.
• I did a quick check to make sure my code changes follow the recommended style guide.