When the user tries to duplicate multiple invoices of different journals,
a traceback will appear.

Steps to reproduce the error:
- Go to Accounting > Configuration > Journals > Create new journal (Type: Sales)
- Go to Customers > Invoices > Create new invoice with newly created journal
- Create another invoice with a different journal
- Select both invoices > Duplicate

Traceback:
```
ValueError: too many values to unpack (expected 1)
  File "odoo/models.py", line 5848, in ensure_one
    _id, = self._ids
ValueError: Expected singleton: account.journal(17, 11)
  File "odoo/http.py", line 2251, in __call__
    response = request._serve_db()
  File "odoo/http.py", line 1827, in _serve_db
    return self._transactioning(_serve_ir_http, readonly=ro)
  File "odoo/http.py", line 1847, 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 1825, in _serve_ir_http
    return self._serve_ir_http(rule, args)
  File "odoo/http.py", line 1832, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
  File "odoo/http.py", line 2057, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
  File "odoo/addons/base/models/ir_http.py", line 220, in _dispatch
    result = endpoint(**request.params)
  File "odoo/http.py", line 739, in route_wrapper
    result = endpoint(self, *args, **params_ok)
  File "addons/web/controllers/dataset.py", line 38, in call_kw
    return 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 "addons/account/models/account_move.py", line 2652, in copy
    new_moves = super().copy(default)
  File "odoo/models.py", line 5563, in copy
    vals_list = self.with_context(active_test=False).copy_data(default)
  File "addons/stock_account/models/account_move.py", line 29, in copy_data
    vals_list = super().copy_data(default=default)
  File "addons/account/models/account_move.py", line 2646, in copy_data
    if not self.journal_id.active and 'journal_id' in vals_list:
  File "odoo/fields.py", line 1202, in __get__
    record.ensure_one()
  File "odoo/models.py", line 5851, in ensure_one
    raise ValueError("Expected singleton: %s" % self)
```

https://github.com/odoo/odoo/blob/6c621e62d4b501bb0626276df798b3f8f585fa75/addons/account/models/account_move.py#L2657
Here, self has multiple records when the user duplicates multiple invoices,
So, it will lead to the above traceback.

sentry-5231989306

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