Fix a few more warnings.

Author: ih-codes

firefox-ios/firefox-ios-tests/Tests/XCUITests/FxScreenGraph.swift

@@ -7,6 +7,7 @@ import Foundation
 import MappaMundi
 import XCTest
 
+@MainActor
 func createScreenGraph(for test: XCTestCase, with app: XCUIApplication) -> MMScreenGraph<FxUserState> {
     let map = MMScreenGraph(for: test, with: FxUserState.self)
 

firefox-ios/firefox-ios-tests/Tests/XCUITests/NavigationRegistry.swift

@@ -6,6 +6,7 @@ import XCTest
 import MappaMundi
 
 enum NavigationRegistry {
+    @MainActor
     static func registerAll(in map: MMScreenGraph<FxUserState>, app: XCUIApplication) {
         registerZoomNavigation(in: map, app: app)
         registerToolBarNavigation(in: map, app: app)