Remove the limitation of using azure packages in dependency

[fengzhou-msft]

With the work of PEP420 and Enable CLI extensions to include packages in the 'azure' namespace, we can remove the check in CI that the dependencies of extension cannot start with azure-. It's blocking #3047.

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This checklist is used to make sure that common guidelines for a pull request are followed.

General Guidelines

• Have you run azdev style <YOUR_EXT> locally? (pip install azdev required)
• Have you run python scripts/ci/test_index.py -q locally?

For new extensions:

• My extension description/summary conforms to the Extension Summary Guidelines.

About Extension Publish

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Once your PR is merged into master branch, a new PR will be created to update src/index.json automatically.
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