[Auth] Add @discardableResult to avoid warnings

FirebaseAuth/Sources/Swift/Auth/Auth.swift

@@ -1613,6 +1613,25 @@ extension Auth: AuthInterop {
         return authURLPresenter.canHandle(url: url)
       }
     }
+
+    /// Handles the given URL if it is recognized by `Auth`.
+    ///
+    /// This method should be called when a URL is received by the scene delegate, ensuring that
+    /// authentication-related URLs are properly processed. It ensures that URLs passed from
+    /// `openURLContexts` are handled by the authentication system.
+    ///
+    /// - Note: This method is available on iOS only.
+    ///
+    /// - Parameter url: The URL received by the application delegate from any of the `openURL`
+    /// methods.
+    @objc open func handle(_ url: URL) throws {
+      guard canHandle(url) else {
+        throw AuthErrorUtils.error(
+          code: AuthErrorCode.internalError,
+          userInfo: [NSLocalizedDescriptionKey: "The URL can't be handled"]
+        )
+      }
+    }
   #endif
 
   /// The name of the `NSNotificationCenter` notification which is posted when the auth state

FirebaseAuth/Tests/Unit/AuthTests.swift

@@ -2364,6 +2364,22 @@ class AuthTests: RPCBaseTests {
       XCTAssertTrue(auth.application(UIApplication.shared, open: url, options: [:]))
       XCTAssertTrue(fakeURLPresenter.canHandled)
     }
+
+    func testAppHandleURL_AuthPresenterHandleURL() throws {
+      class FakeURLPresenter: AuthURLPresenter {
+        var canHandled = false
+        override func canHandle(url: URL) -> Bool {
+          canHandled = true
+          return true
+        }
+      }
+      let url = try XCTUnwrap(URL(string: "https://localhost"))
+      let fakeURLPresenter = FakeURLPresenter()
+      auth.authURLPresenter = fakeURLPresenter
+      XCTAssertFalse(fakeURLPresenter.canHandled)
+      try auth.handle(url)
+      XCTAssertTrue(fakeURLPresenter.canHandled)
+    }
   #endif // os(iOS)
 
   // MARK: Interoperability Tests