create function for getting anonymous ID

Author: russellwheatley

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -307,8 +307,7 @@ public extension AuthService {
       let link = url.absoluteString
 
       if auth.isSignIn(withEmailLink: link) {
-        let anonymousUserID = CommonUtils.getQueryParamValue(from: link, paramName: "continueUrl")
-          .flatMap { CommonUtils.getQueryParamValue(from: $0, paramName: "ui_auid") }
+        let anonymousUserID = CommonUtils.getAnonymousUserIdFromUrl(from: link)
         if shouldHandleAnonymousUpgrade, anonymousUserID == currentUser?.uid {
           let credential = EmailAuthProvider.credential(withEmail: email, link: link)
           try await handleAutoUpgradeAnonymousUser(credentials: credential)

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Utils/CommonUtils.swift

@@ -54,4 +54,9 @@ public class CommonUtils {
 
     return urlComponents.queryItems?.first(where: { $0.name == paramName })?.value
   }
+
+  public static func getAnonymousUserIdFromUrl(from urlString: String) -> String? {
+    getQueryParamValue(from: urlString, paramName: "continueUrl")
+      .flatMap { getQueryParamValue(from: $0, paramName: "ui_auid") }
+  }
 }