[FIX] account: fix zero division when unreconciling caba exch diff

Add move_reverse_cancel=cancel back to context when reconciling moves with reverse moves.

Bug introduced in commit https://github.com/odoo/odoo/commit/e9262bfc8c775953ebe150f36ce0ab8dcb04d4bd



Database : Reproducible in v14, v15
On a Mexican company (with l10n_mx) with multi currencies enabled.
- Set rates for USD to be different at invoice and at payment date
- Create an invoice at date 1 in USD
- Create a payment at date 2 in USD for invoice generating a difference exchange move
- Try to reset the payment to draft
-The traceback (ZeroDivisionError: float division by zero) will appear.

Tickets : 2857549, 2856162, 2855038, 2852663, 2852859, 2857381

closes odoo/odoo#91841

X-original-commit: 7be0fc1d
Signed-off-by: William André (wan) <wan@odoo.com>
Signed-off-by: de Wouters de Bouchout Jean-Benoît (jbw) <jbw@odoo.com>