[Storage] Fix a issue cause SDK breaking change

[blueww]

Description

This is to fix a create/update account failure caused by breaking change of SDK.
The Identity.Type must give a value before send to server now. (Before will have default value since only 1 available value.)

Since there are no interface change, no design doc need.
Since it's a part of upgrade SDK (already in change log), so no additional change log needed.

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
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• 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:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
    • {Please put the link here}
  • the markdown help files have been regenerated using the commands listed here

[blueww]

close, as PR #14307 opened.