Change: remove the ability to control "max spectators" (#9466)

Soon we will make "join game" join the game as spectator first,
so limiting the amount of spectators makes no sense anymore in
that context. Not sure it ever did make sense.

src/table/settings/network_settings.ini

@@ -224,16 +224,6 @@ max      = MAX_CLIENTS
 post_cb  = [](auto) { UpdateClientConfigValues(); }
 cat      = SC_BASIC
 
-[SDTC_VAR]
-var      = network.max_spectators
-type     = SLE_UINT8
-flags    = SF_NOT_IN_SAVE | SF_NO_NETWORK_SYNC | SF_NETWORK_ONLY
-def      = 15
-min      = 0
-max      = MAX_CLIENTS
-post_cb  = [](auto) { UpdateClientConfigValues(); }
-cat      = SC_BASIC
-
 [SDTC_VAR]
 var      = network.restart_game_year
 type     = SLE_INT32