azure-ai-formrecognizer needs typing updates for mypy version 1.10.1

[azure-sdk]

ACTION NEEDED: This version of mypy will be merged on 2024-10-14. The build will begin to fail for this library if errors are not fixed.

Library name: azure-ai-formrecognizer
Mypy version: 1.10.1
Mypy errors: Link to build (2024-10-12)
How to fix: Run the next-mypy tox command at the library package-level and resolve the typing errors.

1. ../azure-ai-formrecognizer>pip install "tox<5"
2. ../azure-ai-formrecognizer>tox run -e next-mypy -c ../../../eng/tox/tox.ini --root .

See the Typing Guide for more information.