Fix to in_array likert bug

Using var_dump in the code shows that $givenAnswer is an integer/string not an array.

To see this error create a survey with a section and two likert questions. Make the second question required and answer the first question but not the second question and click "Submit". You should get errors like this:

Warning: in_array() expects parameter 2 to be array, string given in /home/sitename/public_html/wordpress/wp-content/plugins/wp-survey-and-quiz-tool/pages/site/questions/likert.php on line 5
id="answer_4_1" /> 1   Warning: in_array() expects parameter 2 to be array, string given in /home/sitename/public_html/wordpress/wp-content/plugins/wp-survey-and-quiz-tool/pages/site/questions/likert.php on line 5
id="answer_4_2" /> 2   Warning: in_array() expects parameter 2 to be array, string given in /home/sitename/public_html/wordpress/wp-content/plugins/wp-survey-and-quiz-tool/pages/site/questions/likert.php on line 5....