BED-5065: Display better error messages when creating a new user

[wes-mil]

Description

Display more descriptive and better formatted errors when failing to create a new user.

Motivation and Context

This PR addresses: BED-5065

Why is this change required? What problem does it solve?

Previous error message would not indicate to the admin user why creating a new user was failing to be created.

How Has This Been Tested?

Creating a new user with a duplicate principal name now displays a more descriptive error message.

Screenshots (optional):

Duplicate principal name errors now display as:

Generic errors now display as:

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• I have met the contributing prerequisites
  • Assigned myself to this PR
  • Added the appropriate labels
  • Read the Contributing guide: https://github.com/SpecterOps/BloodHound/wiki/Contributing
• I have ensured that related documentation is up-to-date
  • Open API docs
  • Code comments (GoDocs / JSDocs)
• I have followed proper test practices
  • Added/updated tests to cover my changes
  • All new and existing tests passed

[mistahj67]

Code LGTM, please have someone test this locally to verify UI changes

[ALCooper12]

Code LGTM and the UI displays the error message properly 👍🏾