See [1], `enable_view()` is now in charge of disabling the already possibly
existing template header (and/or footer).
Disabling `website.template_header_default` was not enough, any of the other
template could have been selected by the user before updating the theme.
Note that when installing a theme the first time on a website, the error won't
occur as `_reset_default_config()` will be called through `_theme_remove()`.
[1]: https://github.com/odoo/odoo/pull/81181
Fixes https://github.com/odoo/upgrade/pull/3048
task-2593407
opw-2680866
opw-2685951
opw-2685124
opw-2679040
closesodoo/design-themes#548
X-original-commit: 9a289ea574
Related: odoo/odoo#81953
Signed-off-by: Romain Derie (rde) <rde@odoo.com>
Xavier Luyckx (xlu)