feat: improve vault error message

[tessstoddard]

Summary of Changes

When we throw a vault exception we are just returning the status so it's not super helpful. This adds the vault error body to the exception

Will help with debugging https://mxcom.atlassian.net/browse/GCU-898

Public API Additions/Changes

None. Behind the scenes

Downstream Consumer Impact

Not much impact. Just improves exception throwing

How Has This Been Tested?

Added unit test. This is also code that I copied over from the java-generic-app. Can really test this locally because it doesn't look like we use vault for local development.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works