Fix issues w/ form not passing on auth state

[rhysyngsun]

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/5923

Description (What does it do?)

This removes the html form + submit button combination because it needs to be a GET request but html forms erase the querystring when the method is GET. A plain anchor tag replaces it because this works the way it needs to.

How can this be tested?

• In keycloak, create a user with no credentials or remove credentials from an existing one
• Go to Learn, click "Login"
• Enter the email address for the above user
• You should be prompted to reset the password for that user
• Perform the password reset
• You should be redirected back to Learn instead of the keycloak account page