[REV] account: Revert "set memo to ref if not payment_reference"

This reverts commit a59f255ef33c47449d028930e15c5390c62e39ed.

github issue: 67098

closes odoo/odoo#67255

X-original-commit: 86e2c6b7
Signed-off-by: oco-odoo <oco-odoo@users.noreply.github.com>
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>