fix: update t0 label const name to disambiguate from high value

[urangel]

Description

Two different constants are created for disambiguation purposes: TIER_ZERO_LABEL and HIGH_VALUE_LABEL.

Motivation and Context

This PR addresses: BED-5524

There was a constant in the BHE repository that is also called TIER_ZERO_LABEL which has a different string value assigned to it. The constant name update helps with disambiguation and makes it clear that these constants do not have the same value.

How Has This Been Tested?

The bug is upstream. The project builds as the updated constant name is updated where it was used.

Screenshots (optional):

Types of changes

• Chore (a change that does not modify the application functionality)
• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have met the contributing prerequisites
  • Assigned myself to this PR
  • Added the appropriate labels
  • Associated an issue: Issues and Pull Requests README #672
  • 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

[mvlipka]

LGTM! Thanks for moving this to the shared UI