Reformatted exception message for cmdlets

[arpit-gagneja]

Description

As of today, the cmdlets just print the top level message. In our service case, that message is not that informative for the customers. For our HTTP responses, we includes details in the response as well which explains the message with more information.

For example, here is the testing snapshot after changes for one cmdlet response. The first error message for changed cmdlet response contains more details whereas the second error message for unchanged cmdlet is not informative.

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

[BethanyZhou]

@dolauli , could you help review this PR? Is this correct way to reformat exception message?

[dolauli]

LGTM