Allow Legacy accounts to login with SSO #389
Description
Original issue title: Convert Non-SSO to SSO accounts upon successful SSO login instead of erroring
Right now, when someone creates a HelpMe legacy account with their UBC email and then try to login with SSO (i.e. "Continue with UBC"), it shows an error telling them that legacy accounts can't use SSO to login.
Instead, I think we should show some interface (either an unclosable modal or seperate page) saying:
There is already a non-SSO UBC HelpMe account made with the email xyz@ubc.ca that was created by clicking "Create Account" in our interface.
Would you like to convert this account into a Single Sign On account?
Once converted, you must always click "Continue with UBC" to login instead of entering your email/password. Nothing else will change, but this cannot be reversed.
Go Back | Convert & Continue
And upon clicking Convert & Continue, it will just update the user's account (delete password field, change account type to SSO, whatever else needs to be changed) and then proceed with logging them in
And the reason why we can show this interface is that we can safely assume that the SSO was successful and thus the person is who they say they are, it's just that there was a legacy account that was already created with the same email.