When creating question types of 'essay box, numeric, and text box' then adding a zero as the response, then viewing all responses show these question as 'No responses for this question.' even though a zero was added as the answer.

Issue similar to https://tracker.moodle.org/browse/CONTRIB-5288

Steps to replicate:

1. Create a questionnaire activity,
2. Add the "Numeric" question type and save questionnaire,
3. Now enter questionnaire and "Answer the questions"
4. Add a zero to numeric question and submit questionnaire,
5. Check your response: Note there is no zero appearing

This is also seen in "Essay Box" (when using plain text) and in text box.

NOTE: the responses only show a zero in the essay box question when 'response format' is set to 'html editor'. If you change this to 'plain text' the zero does not appear

When checking the summary of the responses, the questions that have not displayed the zero are showing with "No responses for this question." even though a zero was entered.