Auto merge of #26970 - mrobinson:fix-animation-delay, r=jdm

animations: Don't apply animation delay to every iteration

The delay should only be applied to the animation before the first
iteration.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

components/style/animation.rs

@@ -483,7 +483,7 @@ impl Animation {
 
         // Update the next iteration direction if applicable.
         // TODO(mrobinson): The duration might now be wrong for floating point iteration counts.
-        self.started_at += self.duration + self.delay;
+        self.started_at += self.duration;
         match self.direction {
             AnimationDirection::Alternate | AnimationDirection::AlternateReverse => {
                 self.current_direction = match self.current_direction {