Reset increasing icon text size

There are some usage with 5 chars that do not fit anymore.
Let's reset for now and maybe introduce later a way for the user
to configure the size

umap/static/umap/map.css

@@ -1307,7 +1307,6 @@ a.add-datalayer:hover,
     vertical-align: middle;
     color: white;
     font-weight: bold;
-    font-size: 1.2rem;
 }
 .umap-circle-icon {
     border: 1px solid white;