remove remaining imports of typing_extensions

[dotlambda]

Description of change

It's not a dependency anymore:

redis-py/pyproject.toml

Line 31 in fb30954

dependencies = ['async-timeout>=4.0.3; python_full_version<"3.11.3"']

Pull Request check-list

Please make sure to review and check all of these items:

• Do tests and lints pass with this change?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?

NOTE: these things are not required to open a PR and can be done
afterwards / while the PR is open.

[petyaslavova]

Hi @dotlambda, thank you for your contribution! We will review your change soon.

[petyaslavova]

You can directly import it from typing and completely remove the typing_extensions import. The typing.Optional is available in our min supported version, which is 3.10