fix: when the system disables registration, users can still register and log in through SSO#4722

NatLee wants to merge 1 commit intousememos:mainusememos/memos:mainfrom

NatLee:fix/system-disable-registration-but-users-can-still-sign-up-with-SSONatLee/memos:fix/system-disable-registration-but-users-can-still-sign-up-with-SSOCopy head branch name to clipboard