Switch to http2 directive for nginx 1.25.1+

Summary:
nginx is deprecating the use of http2 parameter in listen directive.

Yet, servers under Rocky Linux 9.4 still use nginx 1.22.1.

Test Plan: Deployed on webserver-core servers

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D3367