chore: remove the access codes feature flag

.env

@@ -87,10 +87,5 @@ EP_OAUTH2_SCOPES=email,profile,roles
 ###> app/features ###
 # Feature flags, read by config/packages/flagception.yaml. Off here and switched on per
 # deployment in .env.local, so a feature reaches production when its environment says so rather
-# than when it is merged.
-#
-# Door, lift and barrier codes under /access-codes and their admin table. Off until the codes
-# have actually been entered: an empty list of codes is worse than no menu entry, because it
-# reads as "there are none" to somebody standing at the door.
-FEATURE_ACCESS_CODES=false
+# than when it is merged. None at the moment.
 ###< app/features ###