Add a margin to plugin cards to allow menu space.

Since elements in core-list are positioned using transforms, only the
last element's margin takes effect, giving enough space below it to
display its menu without scrollbars.

resources/report/html/loot-plugin-card.html

@@ -34,6 +34,9 @@ loot-clear-metadata
         }
 
         /* Host and front/editor styling. */
+        :host {
+            margin-bottom: 210px;
+        }
         #wrapper {
             display: block;
             background:white;