[Monitor Query] Improve workspace ID troubleshooting

[pvaneck]

There have some cases where customers have been trying to use LogsQueryClient.query_workspace by passing in a resource ID of a workspace resource instead of the workspace ID. Investigation and perhaps some validation should be done for cases like this.

Some options:

• Add validation, checking that workspace ID doesn't begin with subscription/* indicating that resource ID was passed in. Suggest using a workspace ID in this case.
• Improve the docstring with an example workspace ID, so users can see the expected format.
• Improve error message when an invalid/nonexistent workspace ID is passed to the service. Currently, the message returned is The requested path does not exist. This can be improved.

[twacn]

I agree. It is very confusing. For example, the LogAnalyticsManagementClient.workspaces.list returns a Workspace object where the id is actually the resource ID -- the "Workspace ID" is actually called customer_id.