Support `unknown` in scan result policy

Why are we doing this work

Our license_scanning tool returns an unknown license type if it can't identify the license. In scope of this issue, we would like to add support for unknown in Scan Result Policies.

type: scan_result_policy
name: unknown is not allowed
description: ''
enabled: true
rules:
  - type: license_finding
    branches: []
    match_on_inclusion: true
    license_types:
      - UNKNOWN
    license_states: []
actions:
  - type: require_approval
    approvals_required: 1

Relevant links

• Epic

Non-functional requirements

• Documentation: documentation is updated to support new status
• Feature flag:
• Performance:
• Testing:

Implementation plan

Verification steps