Notes: Use --wpds-cursor-control token on add-reaction button

The Lint Styles check enforces using the design system cursor token for
interactive non-link controls (rule added in trunk). Replace 'cursor: pointer'
on .editor-collab-sidebar-panel__add-reaction-button to satisfy the rule.

Author: adamsilverstein

packages/editor/src/components/collab-sidebar/style.scss

@@ -235,7 +235,7 @@
 	border-radius: $radius-round;
 	border: $border-width solid $gray-300;
 	background-color: $white;
-	cursor: pointer;
+	cursor: var(--wpds-cursor-control);
 
 	&:hover {
 		background-color: $gray-100;