[FIX] base: avoid triggering recomputation when deleted selection

In 6b048a8b most issue with trigger causing error when uninstalling a
module were solved.

But there was a particular case if the current uninstallation of modules
there was an update of `ir.model.fields.selection` to be removed. The
unlink of `ir.model.fields.selection` would cause a `setup_models` call
that would add all removed triggers back and possibly down the line
cause an trigger recomputation error.

With this changeset, we do as is already done for ir.model.fields and do
not re-initialize the registry during module uninstallation.

opw-2098915
closes #39796

Signed-off-by: Adrian Torres (adt) <adt@odoo.com>