Posting moves on reconciled account with and without party fails
When posting some moves at once which contain lines for account to reconcile but some lines has a party and some others not, this traceback is raised:
```
Traceback (most recent call lasTraceback (most recent call las`t):
File "/tryton/tryton/trytond/trytond/protocols/dispatcher.py", line 195, in _dispatch
result = rpc.result(meth(*c_args, **c_kwargs))
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/tryton/tryton/trytond/trytond/modules/cimbis/invoice.py", line 48, in post
super(Invoice, cls).post(invoices)
File "/tryton/tryton/trytond/trytond/modules/aeat_347/invoice.py", line 265, in post
super(Invoice, cls).post(invoices)
File "/tryton/tryton/trytond/trytond/modules/account_bank/account.py", line 277, in post
super(Invoice, cls).post(invoices)
File "/tryton/tryton/trytond/trytond/modules/commission_invoice_posted2draft/invoice.py", line 21, in post
super(Invoice, cls).post(invoices)
File "/tryton/tryton/trytond/trytond/modules/account_invoice_company_currency/invoice.py", line 161, in post
super(Invoice, cls).post(invoices)
File "/tryton/tryton/trytond/trytond/model/modelview.py", line 697, in wrapper
return func(cls, records, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/tryton/tryton/trytond/trytond/model/workflow.py", line 37, in wrapper
result = func(cls, filtered, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/tryton/tryton/trytond/trytond/modules/account_invoice/invoice.py", line 1583, in post
cls._post(invoices)
File "/tryton/tryton/trytond/trytond/modules/commission/invoice.py", line 36, in _post
super()._post(invoices)
File "/tryton/tryton/trytond/trytond/modules/sale/invoice.py", line 21, in wrapper
func(cls, invoices)
File "/tryton/tryton/trytond/trytond/modules/sale/invoice.py", line 83, in _post
super()._post(invoices)
File "/tryton/tryton/trytond/trytond/modules/purchase/invoice.py", line 22, in wrapper
func(cls, invoices)
File "/tryton/tryton/trytond/trytond/modules/purchase/invoice.py", line 96, in _post
super()._post(invoices)
File "/tryton/tryton/trytond/trytond/modules/account_invoice_stock/account.py", line 26, in _post
super()._post(invoices)
File "/tryton/tryton/trytond/trytond/modules/account_invoice/invoice.py", line 1604, in _post
Move.post([i.move for i in invoices if i.move.state != 'posted'])
File "/tryton/tryton/trytond/trytond/model/modelview.py", line 697, in wrapper
return func(cls, records, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/tryton/tryton/trytond/trytond/modules/account_statement/account.py", line 72, in post
super().post(moves)
File "/tryton/tryton/trytond/trytond/model/modelview.py", line 697, in wrapper
return func(cls, records, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/tryton/tryton/trytond/trytond/modules/account/move.py", line 470, in post
to_reconcile = Line.browse(sorted(
^^^^^^^
TypeError: '<' not supported between instances of 'party.party' and 'NoneType'
```
issue