Show recovery instead of verification if this is the last session and recovery is set up

* Show recovery instead of verification if this is the last session and recovery is set up

* Rename `recoveryKeyState` to `recoveryState`

* Remove duplicates on session security state changes.

* Fix missing "Save recovery key" button

* Fix unit tests

* Rename `isLastDevice` to `isOnlyDeviceLeft`

* Address PR comments

ElementX/Sources/Services/Client/ClientProxy.swift

@@ -166,6 +166,16 @@ class ClientProxy: ClientProxyProtocol {
         let digest = SHA256.hash(data: data)
         return digest.compactMap { String(format: "%02x", $0) }.joined()
     }()
+    
+    func isOnlyDeviceLeft() async -> Result<Bool, ClientProxyError> {
+        do {
+            let result = try await client.encryption().isLastDevice()
+            return .success(result)
+        } catch {
+            MXLog.error("Failed checking isLastDevice with error: \(error)")
+            return .failure(.failedCheckingIsLastDevice(error))
+        }
+    }
 
     func startSync() {
         guard !hasEncounteredAuthError else {

ElementX/Sources/Services/Client/ClientProxyProtocol.swift

@@ -49,6 +49,7 @@ enum ClientProxyError: Error {
     case failedSearchingUsers
     case failedGettingUserProfile
     case failedSettingUserAvatar
+    case failedCheckingIsLastDevice(Error?)
 }
 
 enum SlidingSyncConstants {
@@ -96,6 +97,8 @@ protocol ClientProxyProtocol: AnyObject, MediaLoaderProtocol {
     
     var secureBackupController: SecureBackupControllerProtocol { get }
     
+    func isOnlyDeviceLeft() async -> Result<Bool, ClientProxyError>
+    
     func startSync()
 
     func stopSync()

ElementX/Sources/Services/Client/MockClientProxy.swift

@@ -42,9 +42,8 @@ class MockClientProxy: ClientProxyProtocol {
     
     lazy var secureBackupController: SecureBackupControllerProtocol = {
         let secureBackupController = SecureBackupControllerMock()
-        secureBackupController.underlyingRecoveryKeyState = .init(CurrentValueSubject<SecureBackupRecoveryKeyState, Never>(.enabled))
+        secureBackupController.underlyingRecoveryState = .init(CurrentValueSubject<SecureBackupRecoveryState, Never>(.enabled))
         secureBackupController.underlyingKeyBackupState = .init(CurrentValueSubject<SecureBackupKeyBackupState, Never>(.enabled))
-        secureBackupController.isLastSessionReturnValue = .success(false)
         return secureBackupController
     }()
 
@@ -54,6 +53,10 @@ class MockClientProxy: ClientProxyProtocol {
         self.roomSummaryProvider = roomSummaryProvider
     }
     
+    func isOnlyDeviceLeft() async -> Result<Bool, ClientProxyError> {
+        .success(false)
+    }
+    
     func startSync() { }
 
     func stopSync() { }