Variable numeric

Changes in 2.1

• This version is compatible with Moodle 5.0.


• Fixed coding style issues.


• Defined excluded hash fields and implemented conversion of legacy backup data
  to align with new question data format (per MDL-83541).


• Fixed bug where numeric subquestion feedback text was displayed inline in combined questions.


• Added new validation to the edit form to ensure teacher's answer is in the correct format.


• Fixed a bug where adding images to feedback resulted in errors for combined numeric subquestions.


• Removed incorrect line breaks from inputs and submitted answers in combined numeric subquestions.


• Adapt mobile app template to Ionic 5


• Automation test failures are fixed.


• Added a new option to the question editing form: "If scientific notation is not formatted correctly",
  allowing users to choose whether to accept a space between the number and unit as a valid response.


• Combined\Numeric: Added "Feedback for correct response" field.


• Added checks for empty variables to prevent save errors on the edit form.