Fixes#43705
Before this commit, There will be tracback on converting currecy if there is not date on tax line.
Now we use current date to as fallback to convert currency.
closesodoo/odoo#44559
X-original-commit: 2b88d71c6e4815334f0edaa24d6041c5facd811e
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>