fix for CollapsibleContainer not overlapping the button

apps/app/src/components/Sidebar/Sidebar.tsx

@@ -135,7 +135,7 @@ const CollapsibleContainer = memo((props: CollapsibleContainerProps): JSX.Elemen
   return (
     <div className={`flex-expand-horiz ${className}`} onMouseLeave={mouseLeaveHandler}>
       <Nav onPrimaryItemHover={primaryItemHoverHandler} />
-      <div className={`sidebar-contents-container flex-grow-1 overflow-y-auto ${openClass}`} style={{ width: collapsibleContentsWidth }}>
+      <div className={`sidebar-contents-container flex-grow-1 overflow-y-auto z-n1 ${openClass}`} style={{ width: collapsibleContentsWidth }}>
         {children}
       </div>
     </div>