Supported "all" as an option when setting key vault access policies

[isra-fel]

Description

Fix #12722

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
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• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
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  • the markdown help files have been regenerated using the commands listed here

[isra-fel]

/azp run azure-powershell - powershell-core

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[isra-fel]

Hi @msJinLei I've fixed the test error. Could you take a look?