Add template filters after being cached

The MemoryCache copy the stored template since 7bbbb91621ab but Genshi
Template clear the filters when copied.

Closes #12963
(grafted from 3111fe5130705da70e46b07e4b7cb47012430964)

--HG--
branch : 6.0

trytond/trytond/report/report.py

@@ -324,8 +324,8 @@ class Report(URLMixin, PoolBase):
             loader = relatorio.reporting.MIMETemplateLoader()
             klass = loader.factories[loader.get_type(mimetype)]
             template = klass(BytesIO(report.report_content))
-            cls._callback_loader(report, template)
             report.set_template_cached(template)
+        cls._callback_loader(report, template)
         data = template.generate(**report_context).render()
         if hasattr(data, 'getvalue'):
             data = data.getvalue()