Regression: git send-email fails with "Use of uninitialized value $address" + "unable to extract a valid address"

Hello,

	$ git send-email --to 'A B <a@b.org>, C D <c@d.org>' lala.patch
	Use of uninitialized value $address in sprintf at /usr/lib/git-core/git-send-email line 1172.
	error: unable to extract a valid address from:

This happens for me with git 2.42.0 and also on master (59167d7d09fd, "The seventeenth batch").

Bisection points at

	a8022c5f7b67 ("send-email: expose header information to git-send-email's sendemail-validate hook")

I didn't try to understand that change and fix the problem.

Best regards Uwe