您不再需要外部调用（container.requestApplicationPermission）。
为了检索名称，您需要首先获取活动用户记录ID，然后使用ID获取共享参与者，最后从CKShare.Participant对象检索名称。你的代码已经这样做了，它的修改器版本看起来像这样：

func fetchUserName(completion: @escaping ( _ fullName:String, _ success:Bool) -> Void) {
        self.container.fetchUserRecordID { (record, error) in
            self.container.fetchShareParticipant(withUserRecordID: record!) { (userID, error) in
                var name: String = ""
        
                self.container.accountStatus { accountStatus, error in
                    if let error = error {
                        print(error.localizedDescription)
                    }
                        
                }

                guard let givenName = userID?.nameComponents?.givenName,
                      let familyName = userID?.nameComponents?.familyName else {
                    completion("", false)
                    print("Unable to fetch user name")
                    return
                }
                    
                let fullName: String = givenName + " " + familyName
                name = fullName

                DispatchQueue.main.async {
                    completion(name, true)
                }
            }
        }
    }

如果尚未启用，则还需要enable CloudKit in your app。

等待版本：

static func getUserInformation() async throws -> (id: String, name: String) {
    do {
        let recordID = try await container.userRecordID()
        let id = recordID.recordName
        
        let participant = try await container.shareParticipant(forUserRecordID: recordID)
        guard let nameComponents = participant.userIdentity.nameComponents else {
            throw CloudKitError.userIdentityUnknownName
        }
        let name = PersonNameComponentsFormatter().string(from: nameComponents)

        return (id, name)
    } catch {
        throw error
    }
}