Improve error handling for New-RubrikMount

[jaapbrasser]

Current Behavior:

Unclear error message is displayed

Expected Behavior:

Better error message

Please provide detailed steps for reproducing the issue.

Get-RubrikVM vm01 | New-RubrikMount

Context:

Failure Logs

Please include any relevant log snippets or files here, IMPORTANT all information will be visible publicly on GitHub. Do not include computer or user names, passwords, API tokens or any identifiable information when submitting failure logs.