fix screenshots on safari (#739)

* fix screenshots on safari

* fix another

Author: Rich-Harris

apps/svelte.dev/src/routes/_home/Testimonials.svelte

@@ -95,6 +95,7 @@
 			transition-property: filter, scale;
 			transition-duration: 0.2s;
 			user-select: none;
+			will-change: filter, transform;
 
 			&:nth-child(1) {
 				top: 0%;

packages/site-kit/src/lib/components/Dropdown.svelte

@@ -36,6 +36,7 @@
 		border-radius: var(--sk-border-radius);
 		z-index: 999;
 		-webkit-transform: var(--safari-fix);
+		will-change: opacity;
 
 		&.align-right {
 			left: auto;