Show a loader while an open group is being joined

Signal/src/Loki/View Controllers/JoinPublicChatVC.swift

@@ -142,8 +142,9 @@ final class JoinPublicChatVC : BaseVC, UIPageViewControllerDataSource, UIPageVie
             transaction.removeObject(forKey: "\(urlAsString).\(channelID)", inCollection: PublicChatAPI.lastMessageServerIDCollection)
             transaction.removeObject(forKey: "\(urlAsString).\(channelID)", inCollection: PublicChatAPI.lastDeletionServerIDCollection)
         }
+        ModalActivityIndicatorViewController.present(fromViewController: navigationController!, canCancel: false) { [weak self] _ in
             PublicChatManager.shared.addChat(server: urlAsString, channel: channelID)
-        .done(on: .main) { [weak self] _ in
+            .done(on: DispatchQueue.main) { [weak self] _ in
                 let _ = PublicChatAPI.setDisplayName(to: displayName, on: urlAsString)
                 let _ = PublicChatAPI.setProfilePictureURL(to: profilePictureURL, using: profileKey, on: urlAsString)
                 let _ = PublicChatAPI.join(channelID, on: urlAsString)
@@ -151,7 +152,8 @@ final class JoinPublicChatVC : BaseVC, UIPageViewControllerDataSource, UIPageVie
                 let _ = syncManager.syncAllOpenGroups()
                 self?.presentingViewController!.dismiss(animated: true, completion: nil)
             }
-        .catch(on: .main) { [weak self] error in
+            .catch(on: DispatchQueue.main) { [weak self] error in
+                self?.dismiss(animated: true, completion: nil) // Dismiss the loader
                 var title = NSLocalizedString("Couldn't Join", comment: "")
                 var message = ""
                 if case HTTP.Error.httpRequestFailed(let statusCode, _) = error, statusCode == 401 || statusCode == 403 {
@@ -162,6 +164,7 @@ final class JoinPublicChatVC : BaseVC, UIPageViewControllerDataSource, UIPageVie
                 self?.showError(title: title, message: message)
             }
         }
+    }
     
     // MARK: Convenience
     private func showError(title: String, message: String = "") {

Signal/src/Loki/View Controllers/NewClosedGroupVC.swift

@@ -189,7 +189,7 @@ final class NewClosedGroupVC : BaseVC, UITableViewDataSource, UITableViewDelegat
                 self?.presentingViewController?.dismiss(animated: true, completion: nil)
                 SignalApp.shared().presentConversation(for: thread, action: .compose, animated: false)
             }.catch(on: DispatchQueue.main) { _ in
-                self?.dismiss(animated: true, completion: nil) // Dismiss the modal
+                self?.dismiss(animated: true, completion: nil) // Dismiss the loader
                 let title = NSLocalizedString("Couldn't Create Group", comment: "")
                 let message = NSLocalizedString("Please check your internet connection and try again.", comment: "")
                 let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)