Accept and decline invites (#806)

* Add accept/decline invite api

* Fix isDirect logic

* Add logic for accepting/decling invites

* Add error handling structure

* Add decline alert

* Add navigation to joined room

* Add generic error

* Add changelog.d file

* Cleanup

* Fix failing UTs

* Add UTs

* Add UI tests

* Cleanup

* Update ref screenshots

* Refactor invitesScreen state

* Improve switch handling in UserSessionFlowCoordinator

* Fix build error

ElementX/Sources/Mocks/Generated/GeneratedMocks.swift

@@ -741,6 +741,40 @@ class RoomProxyMock: RoomProxyProtocol {
             return inviterReturnValue
         }
     }
+    //MARK: - rejectInvitation
+
+    var rejectInvitationCallsCount = 0
+    var rejectInvitationCalled: Bool {
+        return rejectInvitationCallsCount > 0
+    }
+    var rejectInvitationReturnValue: Result<Void, RoomProxyError>!
+    var rejectInvitationClosure: (() async -> Result<Void, RoomProxyError>)?
+
+    func rejectInvitation() async -> Result<Void, RoomProxyError> {
+        rejectInvitationCallsCount += 1
+        if let rejectInvitationClosure = rejectInvitationClosure {
+            return await rejectInvitationClosure()
+        } else {
+            return rejectInvitationReturnValue
+        }
+    }
+    //MARK: - acceptInvitation
+
+    var acceptInvitationCallsCount = 0
+    var acceptInvitationCalled: Bool {
+        return acceptInvitationCallsCount > 0
+    }
+    var acceptInvitationReturnValue: Result<Void, RoomProxyError>!
+    var acceptInvitationClosure: (() async -> Result<Void, RoomProxyError>)?
+
+    func acceptInvitation() async -> Result<Void, RoomProxyError> {
+        acceptInvitationCallsCount += 1
+        if let acceptInvitationClosure = acceptInvitationClosure {
+            return await acceptInvitationClosure()
+        } else {
+            return acceptInvitationReturnValue
+        }
+    }
 }
 class SessionVerificationControllerProxyMock: SessionVerificationControllerProxyProtocol {
     var callbacks: PassthroughSubject<SessionVerificationControllerProxyCallback, Never> {