Updated for UE5.4

[jeffswarts]

*Issue #: 44

Description of changes:

Updates to fix the build in UE 5.4. Mainly added imports and inline to a few methods that were causing linker errors. I'm not sure why the AccountFilterType change is necessary but it was the only way I could get it to build. My guess is DIFFERENCE conflicts with an engine enum or something. If anyone knows how to avoid changing the enum value name let me know and I'll update it