This function retrieves the JWT created by the JavaScript from sign_in_js
and signs the user in as long as the token can be verified.
This function should be called in the server function of a shiny module. Make sure
to call sign_in_js
in the UI function of this module.
sign_in_check_jwt(jwt, session = shiny::getDefaultReactiveDomain())
invisible(NULL)
a reactive returning a Firebase JSON web token for the signed in user.
the shiny session.