If a default server name is set and the current HS URL is the default HS URL,
we'll display that name in the "sign in to" text on the login form.
This can be a bit more user friendly, especially when the HS is delegated to
somewhere such as Modular, since you'll then see "example.com" instead of
"example.modular.im", which you have no direct relationship with as a user.
This is the key bit of https://github.com/vector-im/riot-web/issues/8763 for
login.
J. Ryan Stinnett
f4b7180087