Questions with resized images published under Spanish or French will break in Kolibri

[rtibbles]

Observed behavior

The templates for rendering the Perseus JSON for assessment items do not escape or jsonify the designated width or height of images, e.g.

studio/contentcuration/contentcuration/templates/perseus/multiple_selection.json

Line 6 in 584aabd

"width": {{ image.width }},

(but also true for other question types as well).

This means that in languages that do not use . as the decimal separator, and when the width and height of an image are non-integer, the rendered value will break later JSON parsing, as JSON expects . separated numbers.

Expected behavior

Should always output valid JSON regardless of the currently active translation language.

User-facing consequences

Users publishing their channels when the interface is set to Spanish or French could suffer unpredictable breakages in Kolibri.