leaflet buttons are not translated

for instance the Cancel and Apply buttons (https://github.com/ckan/ckanext-spatial/blob/master/ckanext/spatial/public/js/spatial_query.js#L22) but also 'Zoom in' / 'Zoom out' and 'Draw a rectangle' buttons
I tried using the translation method provided by CKAN (https://docs.ckan.org/en/2.8/contributing/string-i18n.html#internationalizing-strings-in-javascript-code) but with not success

Start with ckanext/spatial/public/js/spatial_query.js around line 22 and the CKAN JavaScript internationalization guide linked in the issue. Check how the Cancel, Apply, Zoom in, Zoom out, and Draw a rectangle labels are defined, then verify that all listed button text is translated.

Written by the indexing model from the issue text.