MP Create Game: remove debug mode requirement to access SP campaigns

The option to play SP campaigns in MP had been locked since support was shaky. I'm not entirely sure
how good it is currently, but games at least seem startable. This will also allow us to get more bug
reports if issues do arise, too.

src/gui/dialogs/multiplayer/mp_create_game.cpp

@@ -95,15 +95,12 @@ mp_create_game::mp_create_game(const config& cfg, ng::create_engine& create_eng)
 	level_types_ = {
 		{ng::level::TYPE::SCENARIO, _("Scenarios")},
 		{ng::level::TYPE::CAMPAIGN, _("Campaigns")},
+		{ng::level::TYPE::SP_CAMPAIGN, _("SP Campaigns")},
 		{ng::level::TYPE::USER_MAP, _("User Maps")},
 		{ng::level::TYPE::USER_SCENARIO, _("User Scenarios")},
 		{ng::level::TYPE::RANDOM_MAP, _("Random Maps")},
 	};
 
-	if(game_config::debug) {
-		level_types_.emplace_back(ng::level::TYPE::SP_CAMPAIGN, _("SP Campaigns"));
-	}
-
 	level_types_.erase(std::remove_if(level_types_.begin(), level_types_.end(),
 		[this](level_type_info& type_info) {
 		return create_engine_.get_levels_by_type_unfiltered(type_info.first).empty();