Fix client_list with multiple client ids

[three-kinds]

Pull Request check-list

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• 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

• The current client_list function will cause ResponseError: Invalid client ID when there are multiple client ids.
• In the current unit test, since the length of clients is 1 and client_id = clients[:-1], client_id is an empty list, so it does not play the role of testing multiple client ids.
• The fix is simple, please check the code.

[petyaslavova]

Hi @three-kinds, thank you for your contribution! Your change will be reviewed soon.

[petyaslavova]

LGTM.