docs: add a workflow to deploy docs on demand and fix an issue

[behnazh-w]

Summary

Adds a dedicated GitHub Actions workflow to enable on-demand deployment of documentation to GitHub Pages, and fixes a documentation issue.

Description of changes

• Introduced a new GitHub Actions workflow that builds and deploys documentation to GitHub Pages on demand when changes are pushed to the main. This workflow provides the ability to update published documentation outside of the standard release process, and makes it easier to address documentation-only changes without waiting for a release.
• This PR also removes an unnecessary type ignore comment, which was caught by the latest version of mypy.