Fix relays UI being available in whitelist/secure mode (#11963)

Fix relays UI referencing relay that is not functional

app/models/relay.rb

@@ -12,8 +12,6 @@
 #
 
 class Relay < ApplicationRecord
-  PRESET_RELAY = 'https://relay.joinmastodon.org/inbox'
-
   validates :inbox_url, presence: true, uniqueness: true, url: true, if: :will_save_change_to_inbox_url?
 
   enum state: [:idle, :pending, :accepted, :rejected]
@@ -74,7 +72,6 @@ class Relay < ApplicationRecord
   end
 
   def ensure_disabled
-    return unless enabled?
-    disable!
+    disable! if enabled?
   end
 end