When a user tries to validate an invoice of the refunded order a traceback will occur.

Steps to produce:

- Install 'l10n_mx_edi_pos' module.
- Switch to a company whose country code is 'MX'(Mexico).
- Open 'Point of Sale' and New Session.
- Select any products > payment > Select payment method > Invoice > Select customer > Validate.
- Click on 'Next Order'.
- Click on 'Refund and select your order.
- Click on refund > payment > Select payment method > Invoice > Validate.
- Error will be generated.

Traceback on sentry:

```
TypeError: can only concatenate str (not "bool") to str
  File "odoo/http.py", line 2252, in __call__
    response = request._serve_db()
  File "odoo/http.py", line 1828, in _serve_db
    return self._transactioning(_serve_ir_http, readonly=ro)
  File "odoo/http.py", line 1848, in _transactioning
    return service_model.retrying(func, env=self.env)
  File "odoo/service/model.py", line 134, in retrying
    result = func()
  File "odoo/http.py", line 1826, in _serve_ir_http
    return self._serve_ir_http(rule, args)
  File "odoo/http.py", line 1833, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
  File "odoo/http.py", line 2058, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
  File "odoo/addons/base/models/ir_http.py", line 222, in _dispatch
    result = endpoint(**request.params)
  File "odoo/http.py", line 740, in route_wrapper
    result = endpoint(self, *args, **params_ok)
  File "addons/web/controllers/dataset.py", line 42, in call_button
    action = self._call_kw(model, method, args, kwargs)
  File "addons/web/controllers/dataset.py", line 34, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "odoo/api.py", line 458, in call_kw
    result = getattr(recs, name)(*args, **kwargs)
  File "home/odoo/src/enterprise/saas-17.1/l10n_mx_edi_pos/models/pos_order.py", line 108, in action_pos_order_invoice
    action_values = super().action_pos_order_invoice()
  File "addons/point_of_sale/models/pos_order.py", line 856, in action_pos_order_invoice
    res = self._generate_pos_order_invoice()
  File "addons/point_of_sale/models/pos_order.py", line 873, in _generate_pos_order_invoice
    move_vals = order._prepare_invoice_vals()
  File "addons/pos_sale/models/pos_order.py", line 32, in _prepare_invoice_vals
    invoice_vals = super(PosOrder, self)._prepare_invoice_vals()
  File "home/odoo/src/enterprise/saas-17.1/l10n_mx_edi_pos/models/pos_order.py", line 150, in _prepare_invoice_vals
    vals['l10n_mx_edi_cfdi_origin'] = '03|' + self.refunded_order_id.account_move.l10n_mx_edi_cfdi_uuid
```

This is because 'l10n_mx_edi_cfdi_uuid' is empty at [1] and a string concatenate with it.

link [1]: https://github.com/odoo/enterprise/blob/1502f8b3e519d41f4a58e2acc846f315f6f5eeda/l10n_mx_edi_pos/models/pos_order.py#L150

This commit solves the above issue while checking the existence of
 'l10n_mx_edi_cfdi_uuid'  while creating  the  invoice for refund_order

sentry-4935781389

Forward-Port-Of: odoo/enterprise#64038
Forward-Port-Of: odoo/enterprise#59873