www/grafana9: fix rc.d script procname

Grafana switched to a unified binary, changing grafana-server to be a
wrapper script that executes grafana server in its place. This patch
fixes procname in the rc.d script, so that rc.d's process name
checking doesn't fail / the service gets properly reported as running.

PR: 270098
MFH: 2023Q1
(cherry picked from commit d2f15374931e8b5c5c360a2ecd7794ff492d8d56)