REFACTOR: Replace some fa-* uses with helpers

plugins/poll/test/javascripts/widgets/discourse-poll-option-test.js.es6

@@ -14,7 +14,7 @@ widgetTest('single, not selected', {
   },
 
   test(assert) {
-    assert.ok(find('li .fa-circle-o:eq(0)').length === 1);
+    assert.ok(find('li .d-icon-circle-o:eq(0)').length === 1);
   }
 });
 
@@ -27,7 +27,7 @@ widgetTest('single, selected', {
   },
 
   test(assert) {
-    assert.ok(find('li .fa-dot-circle-o:eq(0)').length === 1);
+    assert.ok(find('li .d-icon-dot-circle-o:eq(0)').length === 1);
   }
 });
 
@@ -43,7 +43,7 @@ widgetTest('multi, not selected', {
   },
 
   test(assert) {
-    assert.ok(find('li .fa-square-o:eq(0)').length === 1);
+    assert.ok(find('li .d-icon-square-o:eq(0)').length === 1);
   }
 });
 
@@ -59,6 +59,6 @@ widgetTest('multi, selected', {
   },
 
   test(assert) {
-    assert.ok(find('li .fa-check-square-o:eq(0)').length === 1);
+    assert.ok(find('li .d-icon-check-square-o:eq(0)').length === 1);
   }
 });