idx.start() ignores user-provided PKCE parameters (codeChallenge/codeChallengeMethod)

[aleks-demin]

Describe the bug

When calling authClient.idx.start() with custom PKCE parameters (codeChallenge, codeChallengeMethod), the library ignores these values and generates new ones instead.

Expected Behavior:
Library should use provided PKCE parameters instead of generating new ones.
Actual Behavior:
Library silently ignores provided parameters and generates new ones, making token exchange impossible.

Reproduction Steps?

const authClient = new OktaAuth({ /* config */ });

await authClient.idx.start({
  codeChallenge: 'my-custom-challenge',
  codeChallengeMethod: 'S256',
});

SDK Versions

7.12.1

Additional Information?

const interactResponse = await interact(authClient, {
        withCredentials,
        state,
        scopes,
        activationToken,
        recoveryToken,
        maxAge,
        acrValues,
        nonce,
        # codeChallenge, codeChallengeMethod are missing 
      });