An action op that calls Phoenix.LiveView.redirect/2 on the
socket. Full-page reload to an external URL or to a non-live
route in the same app.
Distinct from navigate (live-session push_navigate) and from
push_patch (URL update without remount).
Example
action :go_external do
redirect "https://example.com"
end
action :sign_out do
redirect "/auth/sign_out"
end