[scala-sttp] fix enumeration operator constant name collision

Created by: bgong-mdsol

This PR fixes the issue #10187

Here is the openapi spec that can be used to reproduce the issue and verify the fix.

openapi: 3.0.3
info:
title: The comparison operator
version: '1.0'
paths:
/state:
  get:
    operationId: getReport
    responses:
      '200':
        description: get Report
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Reports'
components:
schemas:
  Reports:
    properties:
      name:
        type: string
      expression:
        items:
          $ref: '#/components/schemas/Condition'
        type: array
  Condition:
    example:
      variable: variable
      operator: =
      comparison_value: comparison_value
    properties:
      variable:
        type: string
      comparison_value:
        type: string
      operator:
        description: The comparison operator.
        enum:
        - =
        - '!='
        - '>'
        - <
        - '>='
        - <=
        type: string
    type: object

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