### Packages impacted by this PR
`@azure/storage-blob`
### Describe the problem that is addressed by this PR
As reported by @EmmaZhu there are currently two issues when interacting
with Azure Disk Storage.
The first is if you try to access a Storage account that is not properly
configured to support bearer challenges. In that case an invalid
`authorization_uri` will be returned. Our code currently makes
assumptions about `authorization_uri`, specifically that it can 'split'
the path part of the URL and reliably get a tenantId. In the case that a
valid tenant is not found, the request can end up refreshing in an
infinite loop.
My solution to this problem is to actually check if what we think is a
tenant id is a valid guid or not. Now in the case where we don't see the
expected `authorization_uri`, we will allow the request to fail with the
401.
The second issue occurs when the initial token scope is set to
`https://storage.azure.com/.default`, but the actual required scope is
`https://disk.azure.com//.default` -- when calculating the new scope we
do not duplicate the forward slash, but since the double forward slash
is **required** by the service, a workaround was needed to add it back
in.
### Are there test cases added in this PR? _(If not, why?)_
Yes
072c3f592b