[FIX] web_editor: use media client width as default mediaWidth

Previously, when trying to compute the optimized width for an image,
if the mediaWidth option was unspecified, _computeOptimizedWidth would
return NaN, and in all the places where it was specified, it was
specified as 1920 meaning it was essentially useless.

This commit makes the media's clientWidth the default value for
mediaWidth, meaning that if options.mediaWidth is unspecified, the size
of the element in the page (if one exists) is used. This allows the
suggested width to be actually useful, instead of always suggesting
1920. Specifying a mediaWidth in the options overrides this value.

task-2215913

closes odoo#47662

Signed-off-by: Quentin Smetz (qsm) <[email protected]>

addons/web_editor/static/src/js/wysiwyg/widgets/media.js

@@ -143,6 +143,7 @@ var FileWidget = SearchableMediaWidget.extend({
             firstFilters: [],
             lastFilters: [],
             showQuickUpload: config.isDebug(),
+            mediaWidth: media && media.clientWidth,
         }, options || {});
 
         this.attachments = [];