Fix checkFormValidity with formName argument

CheckFormValidity was not working in all cases, there was a problem inside the function getElementParentForm( ) which was returning null very often. This is due to the fact that myInputElement.form only works with input element and so if user had validation on let say a <div> or any other Angular element that isn't an input then the getElementParentForm( ) was returning null which was in turn making the checkFormValidity($scope.formName) and $validationSummary not working correctly.