**Expected:** an empty `audiences` array will not attempt any audience validation **Actual:** Passing in an empty `audiences` array to config results in failed validation at https://github.com/apollographql/apollo-mcp-server/blob/cd72dc1777b82118423f0fe757671c6c408c12d6/crates/apollo-mcp-server/src/auth/valid_token.rs#L114