Problems with gameinfo search path parsing

[long0900]

For context, this is the current FileSystem KV in CS2 gameinfo.gi:

FileSystem
{
	SearchPaths
	{
		Game_LowViolence	csgo_lv // Perfect World content override

		Game	csgo
		Game	csgo_imported
		Game	csgo_core
		Game	core

		Mod		csgo
		Mod		csgo_imported
		Mod		csgo_core

		AddonRoot			csgo_addons
		OfficialAddonRoot	csgo_community_addons

		LayeredGameRoot		"../game_otherplatforms/etc" [$MOBILE || $ETC_TEXTURES] //Some platforms do not support DXT compression. ETC is a well-supported alternative.
		LayeredGameRoot		"../game_otherplatforms/low_bitrate" [$MOBILE]
	}

	"UserSettingsPathID"	"USRLOCAL"
	"UserSettingsFileEx"	"cs2_"
}

I noticed some problems in Source2GameInfoProvider initialization:

1. It doesn't always follow top-down order. Due to the KV parsing trying to group multiple values from multiple KVs with a same name into a list, the search order is only correct if the search_path_type are sorted like above. Otherwise, it will be wrong if the KV names have a mixed order.

2. The iterable self.filesystem.get("searchpaths", {}).items() here doesn't always yield a list of search_paths, it will yield a single search_path if there's only 1 KV of that search_path_type. This will turn iterating over a list into character iterating, which is wrong.

3. These problems seem to also exist in Source1GameInfoProvider.

4. Additionally, there are 2 new search path types (Game_LowViolence, OfficialAddonRoot) that need support as well.