fix lint oas3.1 unevaluatedProperties as boolean

[AlbertoFdzM]

What/Why/How?

Fixes lint oas3.1 unevaluatedProperties as boolean by updating lint logic

Reference

#620

Testing

Added the next endpoint to /__tests__/lint/oas3.1/openapi.yaml

  /unevaluated-properties:
    get:
      operationId: getUnevaluatedProperties
      summary: Checks if unevaluetedProperties work
      responses:
        200:
          description: 'OK'
          content:
            application/json:
              schema:
                allOf:
                  - type: object
                    properties:
                      foo:
                        type: string
                  - type: object
                    properties:
                      bar:
                        type: number
                unevaluatedProperties: false
        400:
          description: An error response

Screenshots (optional)

Check yourself

• Code is linted
• Tested with redoc/reference-docs/workflows
• All new/updated code is covered with tests

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

[tatomyr]

Thank you @AlbertoFdzM for your contribution!