Restore contacts from backup

XXClient library

• Improve error handling in UdMultiLookupCallback.

xx-messenger example

• Improve backup restoration.
• Restore contacts.
• Add contact lookup feature.
• Display contact ids.
• Improve sending requests.
• Restore username from restored facts, not from restored params.

Examples/xx-messenger/Sources/RestoreFeature/RestoreFeature.swift

@@ -156,7 +156,13 @@ public let restoreReducer = Reducer<RestoreState, RestoreAction, RestoreEnvironm
           ))
         }
         guard lookupResult.errors.isEmpty else {
-          return .success(.failed(lookupResult.errors))
+          var errors = lookupResult.errors
+          do {
+            try env.messenger.destroy()
+          } catch {
+            errors.append(error as NSError)
+          }
+          return .success(.failed(errors))
         }
         return .success(.finished)
       } catch {