Redesign the picture-in-picture window (#9800)

* Remove unnecessary PipContainer component

* Redesign the picture-in-picture window

* Add a hover effect to the controls

* Clarify that WidgetPip has call-specific behavior

src/components/views/elements/AppTile.tsx

@@ -85,7 +85,7 @@ interface IProps {
     widgetPageTitle?: string;
     showLayoutButtons?: boolean;
     // Handle to manually notify the PersistedElement that it needs to move
-    movePersistedElement?: MutableRefObject<() => void>;
+    movePersistedElement?: MutableRefObject<(() => void) | undefined>;
 }
 
 interface IState {