pf tests: disable epsv for the ftp proxy test

The update to py-twisted 24.7.0 broke EPSV mode in twisted's ftp server.
Work around this by disabling EPSV (and thus using PASV).

PR: 282154
MFC after: 1 week
Sponsored by: Rubicon Communications, LLC ("Netgate")

(cherry picked from commit 9cd6ab45a44607ea862c8bbb2ebaa8a7521178ff)