Before this commit, if a theme record (eg `theme.ir.ui.view`) was deleted,
its copy_ids would not be.
While this is perfectly normal and wanted behavior when this is done in a
website context (to not alter other websites), it shouldn't be the case when
performing a theme update through CLI/Migration (or if the user find a way to
update the module through the UI).
Fixes https://github.com/odoo/upgrade/pull/3048
task-2593407
opw-2680866
opw-2685951
opw-2685124
opw-2679040
closesodoo/odoo#81953
X-original-commit: 3146dd72e6cb07d6e78ca763325f13dd54de0086
Related: odoo/design-themes#548
Signed-off-by: Romain Derie (rde) <rde@odoo.com>
