[FIX] website_sale: unable to edit product price

The less refactoring in 5b65befc
wrongly removed the css directive that hide some elements in edit mode.

As a side effect, the product price was appearing twice when editing a
product. Commit 44ca4317 tempt to fix
it but removed the edition part.

opw:683343

addons/web_editor/static/src/less/web_editor.common.less

@@ -8,6 +8,10 @@ html, body {
     display: none !important;
 }
 
+.editor_enable .css_editable_mode_hidden {
+  display: none !important;
+}
+
 /* ----- Editor (for public user, like forum) ----- */
 .note-toolbar {
     margin-left: 0 !important;

addons/website_sale/views/templates.xml

@@ -434,6 +434,13 @@
           <span itemprop="price" style="display:none;" t-esc="product.price"/>
           <span itemprop="priceCurrency" style="display:none;" t-esc="website.currency_id.name"/>
       </h4>
+      <h4 class="css_non_editable_mode_hidden">
+        <span t-field="product.lst_price"
+            t-field-options='{
+               "widget": "monetary",
+               "display_currency": "product.currency_id"
+           }'/>
+      </h4>
       <h4 class="hidden oe_not_available bg-warning">Product not available</h4>
   </div>
 </template>