bug: add catching for invalid responses from local auth proxy

[LittleBigBug]

If the local auth proxy returns an invalid response, the error should be logged in console and attempt to use configured tokens if available instead of completely breaking the game

[Error  :   BepInEx] Error loading [PSP PAPERS 1.1.0]: System.NullReferenceException: Object reference not set to an instance of an object.
   at TwitchLib.Client.Models.ConnectionCredentials..ctor(String twitchUsername, String twitchOAuth, String twitchWebsocketURI, Boolean disableUsernameCheck, Capabilities capabilities)
   at psp_papers_mod.Twitch.TwitchIntegration..ctor()
   at psp_papers_mod.PapersPSP.Load()
   at BepInEx.Unity.IL2CPP.IL2CPPChainloader.LoadPlugin(PluginInfo pluginInfo, Assembly pluginAssembly) in /home/runner/work/BepInEx/BepInEx/Runtimes/Unity/BepInEx.Unity.IL2CPP/IL2CPPChainloader.cs:line 134
   at BepInEx.Bootstrap.BaseChainloader1.LoadPlugins(IList1 plugins) in /home/runner/work/BepInEx/BepInEx/BepInEx.Core/Bootstrap/BaseChainloader.cs:line 411

[linear]

PAP-29 bug: add catching for invalid responses from local auth proxy