[scala][sttp]fix enum generation for inline-enum of array

Created by: bgong-mdsol

This PR fixed the issue 10055

Here is the openapi spec to reproduce the issue and verify the fix.

openapi: 3.0.3
info:
title: array item is enum
version: '1.0'
paths:
/state:
  get:
    operationId: getUserReport
    responses:
      '200':
        description: get Users
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Users'
components:
schemas:
  Users:
    properties:
      emails:
        items:
          type: string
        type: array
      search:
        enum:
        - first_name
        - last_name
        - email
        - full_name
        type: string
      sort_by:
        items:
          enum:
          - first_name
          - last_name
          - email
          type: string
        type: array
    type: object

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh

  Commit all changed files. This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master. These must match the expectations made by your contribution. You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*. For Windows users, please run the script in Git BASH.
• File the PR against the correct branch: master (6.1.0) (minor release - breaking changes with fallbacks), 7.0.x (breaking changes without fallbacks)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

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