fix SteamUser returns null pointer

[ThisIsKashakov]

For some reason, when I tried to call the VoiceData:GetUncompressedData function in the HolyLib:PreProcessVoiceChat hook, I get the error: Failed to get SteamUser!. I don't know for what reason SteamUser() returns a null pointer, but this is the only solution I could find to fix this error.

[RaphaelIT7]

I would move the init code to the module's init function as stuff is mean to be initialized there.
Since that module doesn't have one you would have to add it.

	// Add it as a class member at the beginning.
	virtual void LuaInit(bool bServerInit) OVERRIDE;
	virtual void Shutdown() OVERRIDE;

void CVoiceChatModule::Init(CreateInterfaceFn* appfn, CreateInterfaceFn* gamefn)
{
	// Move the Init code into here
}

void CVoiceChatModule::Shutdown()
{
	// Set the pointer to null
}

Btw thanks for the PR <3
(Just noticed that the workflow doesn't like PR's.... just ignore it for now, I'll look into that tomorrow xd)

[ThisIsKashakov]

I tried to initialize SteamUser in the CVoiceChatModule::Init function by calling CreateLocalUser, but it ended up with my scrds crashing. So I decided that the best solution was to create a new local anonymous steam user and initialize SteamUser in the hook_CSteam3Server_OnLogonSuccess function hook in the steamworks module and globally declare an empty pointer to ISteamUser in util.h. I hope that this solution will be better than the last one, although it requires the steamworks module to be enabled :)