feat: Change policy validation result from string to object

[john-fletcher-aot]

Description

Change the return type of a validation result from a simple text message to a ValidationResult object. The ValidationResult object has a message property, but also has a type property (violation, warning, requirement, information), a code (e.g. field-validation-error, permit-type-unknown), and an optional reference to the offending field name.

Fixes # ORV2-2222

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [X] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

• [X] Unit tests created for testing different scenarios with ValidationResult objects - verify the correct properties are returned
• [X] Existing unit tests pass

Checklist

• [X] I have read the CONTRIBUTING doc
• [X] I have performed a self-review of my own code
• [X] I have commented my code, particularly in hard-to-understand areas
• [X] I have made corresponding changes to the documentation
• [X] My changes generate no new warnings
• [X] I have added tests that prove my fix is effective or that my feature works
• [X] New and existing unit tests pass locally with my changes
• [X] Any dependent changes have already been accepted and merged

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[sonarcloud[bot]]

Quality Gate passed for 'onroutebc vehicles'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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