Since `company_id` on `worksheet.template` changed due to this a973d7d from a Many2many to a Many2one field.

For example, in v17, a single worksheet template linked to 3 companies via the m2m field was returned as 1 record when opening Design Template. After the upgrade in v18, company_id became m2o, and the same data is split into 3 separate records (one per company).

When trying to add a customization via Studio, the search [fetches](https://github.com/odoo/enterprise/blob/18.0/worksheet/controllers/main.py#L12) records based on the model set on the worksheet. In the new version, Studio
[creates](https://github.com/odoo/enterprise/blob/18.0/worksheet/models/worksheet_template.py#L112)
 a new model, but for existing records the
model is the same across the 3 worksheet records tied to the same template. This causes the search to match all 3 records and raise a SingletonError.

```py
Traceback (most recent call last):
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 2856, in __call__
    response = request._serve_db()
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 2331, in _serve_db
    raise self._update_served_exception(exc)
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 2329, in _serve_db
    return service_model.retrying(serve_func, env=self.env)
  File "/home/odoo/src/odoo/19.0/odoo/service/model.py", line 188, in retrying
    result = func()
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 2384, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 2599, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
  File "/home/odoo/src/odoo/19.0/odoo/addons/base/models/ir_http.py", line 353, in _dispatch
    result = endpoint(**request.params)
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 838, in route_wrapper
    result = endpoint(self, *args, **params_ok)
  File "/home/odoo/src/enterprise/19.0/industry_fsm_report/controllers/main.py", line 9, in edit_view
    action = super().edit_view(view_id, studio_view_arch, operations, model, context)
  File "/home/odoo/src/odoo/19.0/odoo/http.py", line 838, in route_wrapper
    result = endpoint(self, *args, **params_ok)
  File "/home/odoo/src/enterprise/19.0/worksheet/controllers/main.py", line 17, in edit_view
    worksheet_template_to_change._generate_qweb_report_template()
  File "/home/odoo/src/enterprise/19.0/worksheet/models/worksheet_template.py", line 490, in _generate_qweb_report_template
    new_arch = self._get_qweb_arch(worksheet_template.model_id, report_name, form_view_id)
  File "/home/odoo/src/enterprise/19.0/worksheet/models/worksheet_template.py", line 460, in _get_qweb_arch
    if 'name' in row_node.attrib and row_node.attrib['name'] not in self._get_qweb_arch_omitted_fields() and row_node.attrib['name'] in form_view_fields:
  File "/home/odoo/src/enterprise/19.0/worksheet/models/worksheet_template.py", line 378, in _get_qweb_arch_omitted_fields
    'x_%s_id' % self.res_model.replace('.', '_'), 'x_name',  # redundant
  File "/home/odoo/src/odoo/19.0/odoo/orm/fields.py", line 1657, in __get__
    record.ensure_one()
  File "/home/odoo/src/odoo/19.0/odoo/orm/models.py", line 5942, in ensure_one
    raise ValueError("Expected singleton: %s" % self)
ValueError: Expected singleton: worksheet.template(3, 14, 18)
```

OPW: 6389190

Steps to reproduce:
-------------------
1. Install `l10n_mx_edi_pos` and set the company to Mexico.
2. In PoS, make an order with one product and pay it.
3. Open the order in the backend, click "Return Products" to make a refund, but don't pay it, cancel it instead.
4. From the same order, click "Return Products" again to make a second refund, and pay it normally.
5. Go to the orders list, select the main order and the paid refund (not the cancelled one), then Actions > Create Global Invoice.

-> Observation: error in the global invoice.

In the CFDI tab of the main order the line is "Send Global In Error", and hovering on it the detail says "Failed to distribute some negative lines".

Why:
----
When we make the global invoice, we remove the refunds from the order. A cancelled refund was never paid, so we should not count it. But we were counting it too. So we removed the refund amount twice in our case, one for the paid refund, and one for the cancelled one, and we end up with an order with negative amount that cannot be distributed.

The fix:
--------
We now skip the cancelled orders when we search the refunds, the same way it is done above when we collect the refunded orders.

opw-6261404