chore(core): resolve swift 6 errors in dev menu code (#3692)

Author: phantumcode

Amplify/DevMenu/AmplifyDevMenu.swift

@@ -12,6 +12,7 @@ import UIKit
 
 /// Presents a developer menu using the provided `DevMenuPresentationContextProvider`
 /// upon notification from a `TriggerRecognizer`. Default recognizer is a `LongPressGestureRecognizer`
+@MainActor
 public final class AmplifyDevMenu: DevMenuBehavior, TriggerDelegate {
 
     weak var devMenuPresentationContextProvider: DevMenuPresentationContextProvider?

AmplifyTests/DevMenuTests/GestureRecognizerTests.swift

@@ -22,6 +22,7 @@ class GestureRecognizerTests: XCTestCase {
     /// - Then:
     ///    - It should return true
 
+    @MainActor
     func testGestureRecognizerAddedToWindow() {
         let contextProvider = MockDevMenuContextProvider()
         let longPressGestureRecognizer =