Header does not hide Login when BOOL_LTI_RESTRICT_LOGINS_TO_LAUNCHES is true

[clpetersonucf]

BOOL_LTI_RESTRICT_LOGINS_TO_LAUNCHES is an optional environment configuration that restricts user logins to only come from the LMS. In the react update, the login button will remain visible if this option is enabled, though visiting it will result in a 404. Instead it should be hidden completely (or even better, the login page should provide a message that says you can only login from the LMS).