net/termshark: fix wrong PKGNAME in net/wireshark@nox11 dependency

Should have been wireshark-nox11 instead of tshark.

Sponsored by: Berliner Linux User Group e.V.
Reported by: Poudriere warning
Approved by: portmgr (build fix blanket)
Differential Revision: https://reviews.freebsd.org/D38995