Stop lightning striking positions that don't have rain (#4386)

Stops lighting from being able to strike in locations where rain doesn't occur, but allows lightning in adjacent areas where is allowed.

Reviewed-on: VoxeLibre/VoxeLibre#4386
Reviewed-by: the-real-herowl <the-real-herowl@noreply.git.minetest.land>
Co-authored-by: teknomunk <teknomunk@protonmail.com>
Co-committed-by: teknomunk <teknomunk@protonmail.com>

mods/ENVIRONMENT/mcl_weather/thunder.lua

@@ -10,6 +10,10 @@ mcl_weather.thunder = {
 	init_done = false,
 }
 
+lightning.register_on_strike(function(pos, pos2, objects)
+	if not mcl_weather.has_rain(pos) then return nil, true end
+end)
+
 minetest.register_globalstep(function(dtime)
 	if mcl_weather.get_weather() ~= "thunder" then
 		return false