front end validation

[cookiedan42]

Overview

#78

Add front end validation for username and password

Main changes and their rationale(s)

• followed style of text field validation error used in signup/login

Some considerations were y

imported the same checker from login, so we can set stricter rules and standardize

Things to take note of

• user-service response was not standardized, so front end wasn't picking it up
• used existing snackbar for error message
• tldr snackbar for back end errors, text box for front end validation error

Testing

e.g. Simply run:

cypress <some file>.ts

[cookiedan42]

[tanyjnaaman]

Remove this?