[feature]: Case-insensitive usernames - users are unable to login if they use any Upper Case in email address at login

Is there an existing issue for this?

• I have searched the existing issues

Summary

Users are unable to sign in when they use Upper Case characters in their email address at the login page, https://app.plane.so/

Since email addresses are case-insensitive, logins based on email addresses should also be case-insensitive, however it appears that MyEmail@email.com is treated as a different account from myemail@email.com in Plane Cloud.

Why should this be worked on?

Not all users are aware that emails are case-insensitive, and use CamelCase and similar in email addresses. This blocks them from being able to successfully sign in.

1. Go to https://app.plane.so
2. Attempt to log into an existing account using the correct email address for the account but with 1 or more Upper Case letters, e.g. Myemail@email.com or myEmail@email.com
3. Instead of being asked for either a password or to log in with a unique code, a unique code is automatically generated (no password prompt)
4. Enter the code: you are taken back to the login screen with a prompt 'Your account is already registered. Sign In now.' Browser URL is https://app.plane.so/?error_code=5030&error_message=USER_ALREADY_EXIST