[IMP] tools: do not export attribute content

Nodes like
<attribute name="t-on-dragenter.stop.prevent">() => state.dropzoneVisible = true</attribute>
should not be exported in the translations files but
<attribute name="string">Hello World</attribute>
should be kept

It was already the case in the xml processing method for server side
templates.
Since 16.0, client side QWeb views also use the same inheritance
mechanism than the one on the server side so the exception needs to be
replicated.

X-original-commit: e05d1192481935b2cd7aae7e939f98e60e002899
Part-of: odoo/odoo#101053

odoo/tools/translate.py

@@ -849,6 +849,7 @@ def _extract_translatable_qweb_terms(element, callback):
         if (el.tag.lower() not in SKIPPED_ELEMENTS
                 and "t-js" not in el.attrib
                 and not ("t-jquery" in el.attrib and "t-operation" not in el.attrib)
+                and not (node.tag == 'attribute' and el.get('name') not in TRANSLATED_ATTRS)
                 and el.get("t-translation", '').strip() != "off"):
 
             _push(callback, el.text, el.sourceline)