Update licenses validation

What does this MR do and why?

This MR updates the security policy schema to prevent the use of the licenses field together with licenses_type and match_on_inclusion_license. This change was discussed here and is also being added in the frontend.

References

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MR acceptance checklist

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Screenshots or screen recordings

How to set up and validate locally

1. Create a new project
2. Go to Secure > Policies
3. Click in New policy
4. Select Merge request approval policy
5. Try to create a policy using licenses, license_types, and match_on_inclusion_license

Something like:

type: approval_policy
name: abcd
description: ''
enabled: true
rules:
  - type: license_finding
    match_on_inclusion_license: true
    license_types:
      - MIT License
    license_states:
      - newly_detected
    branches: []
    licenses:
      denied:
        - name: MIT License
actions:
  - type: require_approval
    approvals_required: 1
    role_approvers:
      - owner
  - type: send_bot_message
    enabled: true
approval_settings:
  block_branch_modification: true
  prevent_pushing_and_force_pushing: true
  prevent_approval_by_author: true
  prevent_approval_by_commit_author: true
  remove_approvals_with_new_commit: true
  require_password_to_approve: false
fallback_behavior:
  fail: closed

6. Verify the policy is invalid