FIXUP: use empty! instead of empty div!

Co-authored-by: Tobias Reiher <15232394+treiher@users.noreply.github.com>

Author: Alexander Senier

frontend/src/common.rs

@@ -601,7 +601,7 @@ pub fn view_chart<Ms>(
                     C!["has-text-centered"],
                     C!["mb-4"],
                     "No data.".to_string(),
-                ] } else { div![] },
+                ] } else { empty![] },
             Some(value) => div![
                 C!["container"],
                 C!["has-text-centered"],