Update widget_toolkit_otp and example project

[DDavidPrime]

Overview

One in a series of PRs to cover the widget_toolkit ecosystem update to support latest version of packages.

Checklist

Implementation

• Implementation matches ticket acceptance criteria and technical notes
• Manually tested against Acceptance Criteria
• UI checked on Android / iOS

Stability

• Checked if changes affect any features and verified affected features work as expected
  - [ ] Added unit tests for new code and verified existing tests work as expected

Code quality

• Updated CHANGELOG.md, README.md and package versions in pubspec.yaml
• Dependencies are updated to latest versions or new tickets are created if there are breaking changes or deprecations
  - [ ] If an unrelated part of the codebase needs to be updated or refactored, create tickets with proposed changes

[GoranPrime]

Due to the breaking change with pinput and smart_auth, I think it's worth testing this functionality more thoroughly, when we're done with the updates