[Storage] az storage account migration: Remove preview version as it has been GA in main repo

[calvinhzy]

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

Related command

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? (pip install wheel==0.30.0 required)
• My extension version conforms to the Extension version schema

For new extensions:

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

About Extension Publish

There is a pipeline to automatically build, upload and publish extension wheels.
Once your pull request is merged into main branch, a new pull request will be created to update src/index.json automatically.
You only need to update the version information in file setup.py and historical information in file HISTORY.rst in your PR but do not modify src/index.json.

[azure-client-tools-bot-prd]

❌Azure CLI Extensions Breaking Change Test

❌storage-preview

rule	cmd_name	rule_message	suggest_message
❌ 1012 - SubgroupRemove	storage account migration	sub group storage account migration removed	please confirm sub group storage account migration removed
❌ 1012 - SubgroupRemove	storage directory	sub group storage directory removed	please confirm sub group storage directory removed
❌ 1012 - SubgroupRemove	storage file	sub group storage file removed	please confirm sub group storage file removed
❌ 1012 - SubgroupRemove	storage share	sub group storage share removed	please confirm sub group storage share removed

[yonzhan]

Storage

[github-actions]

For more info about extension versioning, please refer to Extension version schema