Fix `"vkxscp096:trigger"` net exploit where you can trigger from anywhere (clientside detection only)

Despite the Clientside detection method's description being explicit on exploits, the fact that you can trigger any SCP-096 from anywhere should be at least secured.

Conditions may rely, at best, on PVS using Entity/TestPVS or on a maximum distance radius (or any other better solutions).

Relevant code:

guthscp096/lua/autorun/server/sv_vkx_scp_096.lua

Lines 288 to 295 in 818b97f

    
           net.Receive( "vkxscp096:trigger", function( len, ply ) 
        
           	if not ( GuthSCP.Config.vkxscp096.detection_method == GuthSCP.DETECTION_METHODS.CLIENTSIDE ) then return end 
        
           	local scp = net.ReadEntity() 
        
           	if not IsValid( scp ) or not GuthSCP.isSCP096( scp ) then return end 
        
           	GuthSCP.triggerSCP096( ply, scp ) 
        
           end )

	net.Receive( "vkxscp096:trigger", function( len, ply )
	if not ( GuthSCP.Config.vkxscp096.detection_method == GuthSCP.DETECTION_METHODS.CLIENTSIDE ) then return end

	local scp = net.ReadEntity()
	if not IsValid( scp ) or not GuthSCP.isSCP096( scp ) then return end

	GuthSCP.triggerSCP096( ply, scp )
	end )