feat: Add exception to onVerificationFailed callback

[flxapps]

Updated the onIdentificationFailed callback to include an ImpReaderException parameter, providing detailed error information to consumers.

Breaking Changes

⚠️ This is a breaking change

All consumers must update their onIdentificationFailed callback:

Before:

onIdentificationFailed: () {
  print('Identification failed');
}

After:

onIdentificationFailed: (exception) {
  print('Identification failed: ${exception.message}');
}

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[JoshuaWell]

LGTM 👍🏻