chore: remove trailing whitespace in package.json that was failing CI

- yarn nx format:check --base origin/master

packages/react-components/react-message-bar/library/package.json

@@ -22,7 +22,7 @@
     "@fluentui/react-icons": "^2.0.245",
     "@fluentui/react-jsx-runtime": "^9.0.48",
     "@fluentui/react-motion": "^9.6.4",
-    "@fluentui/react-motion-components-preview": "^0.4.0",    
+    "@fluentui/react-motion-components-preview": "^0.4.0",
     "@fluentui/react-shared-contexts": "^9.21.2",
     "@fluentui/react-link": "^9.3.5",
     "@fluentui/react-theme": "^9.1.24",

packages/react-components/react-message-bar/library/src/components/MessageBarGroup/MessageBarGroup.motions.tsx

@@ -2,23 +2,28 @@ import { motionTokens, createPresenceComponent, PresenceDirection, AtomMotion }
 
 // TODO: import these atoms from react-motion-components-preview once they're available there
 
+interface FadeAtomParams {
+  direction: PresenceDirection;
+  duration: number;
+  easing?: string;
+  fromValue?: number;
+}
+
 /**
  * Generates a motion atom object for a fade in or fade out.
  * @param direction - The functional direction of the motion: 'enter' or 'exit'.
  * @param duration - The duration of the motion in milliseconds.
  * @param easing - The easing curve for the motion. Defaults to `motionTokens.curveLinear`.
+ * @param fromValue - The starting opacity value. Defaults to 0.
  * @returns A motion atom object with opacity keyframes and the supplied duration and easing.
  */
 const fadeAtom = ({
   direction,
   duration,
   easing = motionTokens.curveLinear,
-}: {
-  direction: PresenceDirection;
-  duration: number;
-  easing?: string;
-}): AtomMotion => {
-  const keyframes = [{ opacity: 0 }, { opacity: 1 }];
+  fromValue = 0,
+}: FadeAtomParams): AtomMotion => {
+  const keyframes = [{ opacity: fromValue }, { opacity: 1 }];
   if (direction === 'exit') {
     keyframes.reverse();
   }