fix bug for a parameter as a list

[yadongyaly]

The PR is to fix a bug for the new CLI commands "az datamigration login-migration".

Local Test:
with this fix, it can migrate logins of source database to the target database.

Below image is the logins of target MI server, the new logins are from the source database by running this CLI command:

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[ghost]

Thank you for your contribution yadongyaly! We will review the pull request and get back to you soon.

[yonzhan]

data migration

[yadongyaly]

Hi @evelyn-ys , @yonzhan @calvinhzy

Can I get a quick review of this smale PR?

[evelyn-ys]

If you want to release a new version, don't forget to update the setup.py and history.rst file

[yadongyaly]

If you want to release a new version, don't forget to update the setup.py and history.rst file

Thanks @evelyn-ys for providing the review and comments. i have upgraded the version in those two files.

[azclibot]

[Release] Update index.json for extension [ datamigration ] : https://dev.azure.com/azclitools/internal/_build/results?buildId=46180&view=results