[FIX] mass_mailing: fix traceback on picking shape

Picking a shape for an image in mass_mailing (when in developer mode)
would result in a sudden error due to a None
being passed to _getCSSColorValue

The shape picker is completely hidden in  the mass_mailing
templates editor as essentially no mail
client supports it in this version up to 15.3

Feature properly reintroduced in:
https://github.com/odoo/odoo/pull/84926



Task-2937490

closes odoo/odoo#97042

Signed-off-by: Warnon Aurélien (awa) <awa@odoo.com>

addons/mass_mailing/static/src/js/mass_mailing_snippets.js

@@ -133,7 +133,8 @@ options.registry.ImageOptimize.include({
         // feature.
         const imgShapeContainerEl = this.el.querySelector('.o_we_image_shape');
         if (imgShapeContainerEl) {
-            imgShapeContainerEl.classList.toggle('d-none', !odoo.debug);
+            // Hidden from view as the feature is not yet supported in emails
+            imgShapeContainerEl.classList.add('d-none');
         }
     },