[FEATURE] ValidationResultOperation for UC storage credential validation should include PATH_EXISTS and HIERARCHICAL_NAMESPACE_ENABLED

[qziyuan]

Problem Statement
When validate UC storage credential using SDK, the returned response will contain two None operations. It's because PATH_EXISTS and HIERARCHICAL_NAMESPACE_ENABLED are missing in ValidationResultOperation

Proposed Solution
Support those two missing validate operations.

Additional Context
Add any other context, references or screenshots about the feature request here.

[mgyucht]

Thank you for reporting this. I've created a ticket for the Unity Catalog team to update their API definition.