Add support for sharing URLs and text. (#3546)

* Add support for sharing URLs and text.

* Fix a bug where a stored draft would overwrite the shared text.

* Add tests.

ElementX/Sources/Other/Extensions/NSItemProvider.swift

@@ -6,7 +6,7 @@
 //
 
 import Foundation
-import UIKit
+import SwiftUI
 import UniformTypeIdentifiers
 
 extension NSItemProvider {
@@ -15,6 +15,19 @@ extension NSItemProvider {
         let fileExtension: String
     }
     
+    func loadTransferable<T: Transferable>(type transferableType: T.Type) async -> T? {
+        try? await withCheckedContinuation { continuation in
+            _ = loadTransferable(type: T.self) { result in
+                continuation.resume(returning: result)
+            }
+        }
+        .get()
+    }
+    
+    func loadString() async -> String? {
+        try? await loadItem(forTypeIdentifier: UTType.text.identifier) as? String
+    }
+    
     func storeData() async -> URL? {
         guard let contentType = preferredContentType else {
             MXLog.error("Invalid NSItemProvider: \(self)")