[CAL-3600] SAML/SSO idP auto-merging allows slipping of uppercase in email

[alishaz-polymath]

When we merge identities in the next-auth-options, if the idP passes email with uppercase characters, it slips the email with uppercase characters and the account merging causes the user's email to be updated with said uppercase characters. This results in a non-usable state of the user's account and in turn creates a new account for the user when attempted to login.
A potential fix is to probably identify the source where email is updated with uppercase and simply force lowercase there.

_{From SyncLinear.com | CAL-3600}

[alishaz-polymath]

While at it, probably a good idea to improve description for pasting the XML Metadata in the SAML/SSO Setup step