Fix multi sync screen showing wrong player status for non-host players (scp-fs2open#7359)

Net_player[idx] (pointer arithmetic from current player) was used instead
of Net_players[idx] (global array index), causing the status display to
read from wrong offsets. This coincidentally worked for the host at index 0
but showed incorrect status for all other players — most visibly on
standalone servers where no client is at index 0.

Fixes scp-fs2open#7358

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: chief1983

code/network/multiui.cpp

@@ -7821,7 +7821,7 @@ void multi_sync_blit_screen_all()
 			// display his name and status
 			multi_sync_display_name(Net_players[idx].m_player->callsign,count,idx);
 
-			multi_sync_display_status(multi_sync_get_state_string(&Net_player[idx]).c_str(), count);
+			multi_sync_display_status(multi_sync_get_state_string(&Net_players[idx]).c_str(), count);
 			count++;
 		}
 	}