feat: add dark background to Results table and graph (#5287)

* feat: add dark background to Results table and graph

* chore: css select a classname `giraffe-plot`

Author: appletreeisyellow

src/dataExplorer/components/Results.scss

@@ -31,6 +31,15 @@ $cf-radius-lg: $cf-radius + 4px;
   height: 100%;
   width: 100%;
   padding: 12;
+
+  .visualization--simple-table--results {
+    margin-top: $cf-space-s;
+  }
+
+  table,
+  .giraffe-plot {
+    background-color: black;
+  }
 }
 
 .data-explorer-results--empty-header {