fix: Rename "advanced" presence to "rich" presence

Removed debug leftovers

fix: Rename WL Prefab Readme to .md

fix: Compilation issues for < Unity Version

Bump version to 6.4.0

ci: Update Unity test runner

fix: Fix refresh and retry logic

Bump version to v6.1.0

fix: Make last_seen nullable

Bump version to 5.3.0