987fc1190a had added a rule that made
empty fields non-editable so that a snippetless website would not be
editable. This makes empty t-fields non-editable as well which is - to
say the least - not welcome.
This commit fixes that problem by making the rule more restrictive: what
we don't want to be able to edit are empty _arch_ field specifically.
closesodoo/odoo#71718
X-original-commit: 6886c2a2a2ad47d1150dd072888c39ccfb59b163
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>