Customizer: make utilities.less inclusion mandatory

Fixes #13305.

docs/customize.html

@@ -58,6 +58,12 @@ lead: Customize Bootstrap's components, Less variables, and jQuery plugins to ge
             Buttons
           </label>
         </div>
+        <div class="checkbox">
+          <label>
+            <input type="checkbox" checked value="responsive-utilities.less">
+            Responsive utilities
+          </label>
+        </div>
       </div><!-- .col-xs-6 .col-sm-4 -->
 
       <div class="col-xs-6 col-sm-4">
@@ -88,7 +94,7 @@ lead: Customize Bootstrap's components, Less variables, and jQuery plugins to ge
         </div>
         <div class="checkbox">
           <label>
-            <input type="checkbox" checked value="navbar.less" data-dependencies="forms.less,utilities.less,navs.less">
+            <input type="checkbox" checked value="navbar.less" data-dependencies="forms.less,navs.less">
             Navbar
           </label>
         </div>
@@ -222,20 +228,6 @@ lead: Customize Bootstrap's components, Less variables, and jQuery plugins to ge
             Carousel
           </label>
         </div>
-
-        <h3>Utilities</h3>
-        <div class="checkbox">
-          <label>
-            <input type="checkbox" checked value="utilities.less" data-dependents="navbar.less">
-            Basic utilities
-          </label>
-        </div>
-        <div class="checkbox">
-          <label>
-            <input type="checkbox" checked value="responsive-utilities.less">
-            Responsive utilities
-          </label>
-        </div>
       </div><!-- .col-xs-6 .col-sm-4 -->
     </div><!-- /.row -->
   </div>