Show share if available

Trust/Transactions/ViewControllers/TransactionViewController.swift

@@ -63,7 +63,9 @@ class TransactionViewController: UIViewController {
 
         displayChildViewController(viewController: stackViewController)
 
-        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(share(_:)))
+        if viewModel.shareAvailable {
+            navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(share(_:)))
+        }
     }
 
     private func item(title: String, value: String) -> UIView {

Trust/Transactions/ViewModels/TransactionDetailsViewModel.swift

@@ -56,6 +56,10 @@ struct TransactionDetailsViewModel {
         }
     }
 
+    var shareAvailable: Bool {
+        return detailsAvailable
+    }
+
     var detailsURL: URL {
         return ConfigExplorer(server: config.server).transactionURL(for: transaction.id)
     }