fixed snapshots failing in master

packages/grafana-ui/src/components/CustomScrollbar/__snapshots__/CustomScrollbar.test.tsx.snap

@@ -2,7 +2,7 @@
 
 exports[`CustomScrollbar renders correctly 1`] = `
 <div
-  className="custom-scrollbars"
+  className="custom-scrollbar"
   style={
     Object {
       "height": "auto",

public/app/features/admin/__snapshots__/ServerStats.test.tsx.snap

@@ -5,7 +5,7 @@ exports[`ServerStats Should render table with stats 1`] = `
   className="page-scrollbar-wrapper"
 >
   <div
-    className="custom-scrollbars"
+    className="custom-scrollbar custom-scrollbar--page"
     style={
       Object {
         "height": "auto",

public/app/features/dashboard/containers/__snapshots__/DashboardPage.test.tsx.snap

@@ -109,7 +109,6 @@ exports[`DashboardPage Dashboard init completed  Should render dashboard grid 1`
       autoHide={false}
       autoHideDuration={200}
       autoHideTimeout={200}
-      customClassName="custom-scrollbars"
       hideTracksWhenNotNeeded={false}
       scrollTop={0}
       setScrollTop={[Function]}
@@ -345,7 +344,6 @@ exports[`DashboardPage When dashboard has editview url state should render setti
       autoHide={false}
       autoHideDuration={200}
       autoHideTimeout={200}
-      customClassName="custom-scrollbars"
       hideTracksWhenNotNeeded={false}
       scrollTop={0}
       setScrollTop={[Function]}