mod_data: Missing validation of image width and height

Requirements

• Server running on PHP 7.4 but can be switched to run PHP 8.0

Before the patch

1. Use PHP 7.4
2. As teacher, create database activity in a course
3. Add a new field of type "Image"
4. Insert a name for the field
5. Insert a non-numeric value for the following fields (e.g. "214px", etc.):
   • Width (in pixels) in single view
   • Height (in pixels) in single view
   • Width (in pixels) in list view
   • Height (in pixels) in list view
6. Click "Save"

Test: After the patch

1. Switch to PHP 8.0
2. Add an entry for database, setting a picture for the Image field you created earier.
3. Save the entry.
4. Confirm that you don't get any error
5. Confirm that the image you entered is rendered in both List and Single views.
6. Edit the image field.
7. Confirm that the non-numeric width/height values are now empty.
8. Confirm that you can only enter numeric values (e.g. numbers, decimal point)
9. Save the form.
10. Apply the test patch to revert the width/height text fields to accept non-numeric inputs.

    git apply MDL-76525-test.diff

11. Enter non-numeric values for the width/height inputs.
12. Save the changes.
13. Confirm that the page is reloaded with an error notification listing the fields that have invalid values.
14. Create a new image field
15. Enter non-numeric values for the width/height inputs.
16. Save the changes.
17. Confirm that the page is reloaded with an error notification listing the fields that have invalid values. (You'll notice that the inputs are blank again when the page reloads. This is okay).

After test

• Make sure to revert the changes from MDL-76525-test.diff

  git reset --hard