environment: Adjust optional delay parameter

All timing parameters should take the `slow-down-factor` and
`enable-animations` settings into account, but the delay parameter
of property/adjustment animations was forgotten.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2986>

js/ui/environment.js

@@ -174,6 +174,9 @@ function _easeActorProperty(actor, propName, target, params) {
         params.duration = adjustAnimationTime(params.duration);
     let duration = Math.floor(params.duration || 0);
 
+    if (params.delay)
+        params.delay = adjustAnimationTime(params.delay);
+
     const repeatCount = params.repeatCount;
     delete params.repeatCount;