Redis.from_url returns Redis, not None

[martimors]

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)?
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Description of change

Pyright picked up this issue. Looks like it was introduced in #2952 (otherwise an excellent and very welcome contribution). No functional changes, just metadata.

[dvora-h]

Fixed in #2963