fix: Filters sidebar stretching dashboard height (#27069)

(cherry picked from commit 3f91bdb)

superset-frontend/src/dashboard/components/DashboardBuilder/DashboardWrapper.tsx

@@ -25,6 +25,7 @@ import classNames from 'classnames';
 
 const StyledDiv = styled.div`
   ${({ theme }) => css`
+    position: relative;
     display: grid;
     grid-template-columns: auto 1fr;
     grid-template-rows: auto 1fr;