www/py-grip: Update to 4.6.1

This version adds support for Flask (www/py-flask) >= 2.1.0. Previous
versions of grip will crash due to the missing safe_join function which
was removed from Flask in version 2.1.0. Fixes [1].

PR: 263115 [1]
Reported by: jwb [1]
MFH: 2022Q2