[IMP] web: add a small padding-top to the graph container

addons/web/static/src/scss/graph_view.scss

@@ -2,6 +2,7 @@
     .o_graph_renderer {
         height: 100%;
         .o_graph_canvas_container {
+            padding-top: 5px;
             position: relative;
             height: 100%;
             width: 100%;