explorer: fix broken layout

Applying this control tweak globally broke the explorer layout. So we
now apply it to settings only.

src/activities/activities.scss

@@ -39,9 +39,5 @@
             height: 100%;
             z-index: bp.$pt-z-index-overlay;
         }
-
-        .#{bp.$ns}-control {
-            max-width: bp.$pt-grid-size * 20;
-        }
     }
 }

src/settings/settings.scss

@@ -15,4 +15,8 @@
             width: bp.$pt-grid-size * 20;
         }
     }
+
+    & .#{bp.$ns}-control {
+        max-width: bp.$pt-grid-size * 20;
+    }
 }