fix: update pre-built searches to avoid potentially comparing defined…

[urangel]

… types with null values

Description

The prebuilt search list has been updated so that we are not comparing potentially null values to defined types.

Motivation and Context

This PR addresses: BED-5415

Some of the queries are not working currently.

How Has This Been Tested?

The queries were executed manually in a test environment to check for any errors.
A test was added to find labels that deviate from our schema which catches typos in the hard coded query strings.

Screenshots (optional):

Types of changes

• 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

[StephenHinck]

Biggest issues were around the replacement of the previously hardcoded admin_tier_0 string with variable replacement, which still needs quotes. Others were questions about whether it's CySQL or direct syntax problems.

[StephenHinck]

Please double-check the two questions around CySQL, but presuming those are CySQL related, this looks good!