Fix find instance VC requiring double dismiss

Tusker/Screens/FindInstanceViewController.swift

@@ -37,7 +37,14 @@ class FindInstanceViewController: InstanceSelectorTableViewController {
     // MARK: - Interaction
     
     @objc func cancelButtonPressed() {
-        dismiss(animated: true)
+        // when the search controller is active, dismiss exits it rather than dismissing ourself, so we have to dismiss twice
+        if searchController.isActive {
+            dismiss(animated: false) {
+                self.dismiss(animated: true)
+            }
+        } else {
+            dismiss(animated: true)
+        }
     }
 
 }