fix(auth, expo): lowercase String? in swift using .lowercased()

Author: f5io

packages/auth/plugin/__tests__/__snapshots__/iosPlugin_openUrlFix.test.ts.snap

@@ -355,7 +355,7 @@ public class AppDelegate: ExpoAppDelegate {
     options: [UIApplication.OpenURLOptionsKey: Any] = [:]
   ) -> Bool {
 // @generated begin @react-native-firebase/auth-openURL - expo prebuild (DO NOT MODIFY)
-    if url.host.toLowerCase() == "firebaseauth" {
+    if url.host?.lowercased() == "firebaseauth" {
       // invocations for Firebase Auth are handled elsewhere and should not be forwarded to Expo Router
       return false
     }

packages/auth/plugin/src/ios/openUrlFix.ts

@@ -155,7 +155,7 @@ export function modifyObjcAppDelegate(contents: string): string | null {
 // NOTE: `mergeContents()` doesn't support newlines for the `anchor` regex, so we have to replace it manually
 const skipOpenUrlForFirebaseAuthBlockSwift: string = `\
 // @generated begin @react-native-firebase/auth-openURL - expo prebuild (DO NOT MODIFY)
-    if url.host.toLowerCase() == "firebaseauth" {
+    if url.host?.lowercased() == "firebaseauth" {
       // invocations for Firebase Auth are handled elsewhere and should not be forwarded to Expo Router
       return false
     }