test(theme): remove duplicated case

we are already checking it in helper's test

Author: Kamil Kisiela

tests/runs/md-theme-manipulator-spec.js

@@ -28,7 +28,7 @@ describe("formlyMaterial - theme manipulator", () => {
         }, options)];
 
         let form = $compile(testUtils.getFormTemplate())($scope);
-        
+
         $scope.$digest();
         element = form.find('[ng-model]');
         field = $scope.fields[0];
@@ -55,13 +55,4 @@ describe("formlyMaterial - theme manipulator", () => {
         expect(element.attr('md-theme')).toBe('custom');
     });
 
-    it("should be able to skip md-theme", () => {
-        compile({
-            extras: {
-                skipNgModelAttrsManipulator: true
-            }
-        });
-        expect(element.attr('md-theme')).toBeUndefined();
-    });
-
-});
+});