lua: make "net" namespace available to extensions

Close #9495

modules/lua/extension.c

@@ -821,6 +821,7 @@ static lua_State* GetLuaState( extensions_manager_t *p_mgr,
             luaopen_dialog( L, p_ext );
             luaopen_input( L );
             luaopen_msg( L );
+            luaopen_net( L );
             luaopen_object( L );
             luaopen_osd( L );
             luaopen_playlist( L );