TF-2384 Handle refresh token when token expired in NSE

Signed-off-by: dab246 <tdvu@linagora.com>
(cherry picked from commit c8a39bb42792770c001ac90d6301d53126225d95)

ios/TwakeCore/Extensions/StringExtensions.swift

@@ -0,0 +1,12 @@
+import Foundation
+
+extension String {
+    func convertISO8601StringToDate() -> Date? {
+        let dateFormatter = ISO8601DateFormatter()
+        dateFormatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+        if let date = dateFormatter.date(from: self) {
+            return date
+        }
+        return nil
+    }
+}