[BUG] Incorrect enum values for typescript clients

Created by: epidemia

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Description

Enum values are generated incorrectly for PascalCase enum property naming type when the source enum values are in uppercase with underscores. For example, original enum values:

"BookType": {
        "type": "string",
        "description": "Book Type",
        "example": "SCIENCE",
        "enum": [
          "SCIENCE",
          "SCIENCE_FICTION"
        ]
      }

Expected enum values:

export enum BookType {
  Science = 'SCIENCE',
  ScienceFiction = 'SCIENCE_FICTION'
}

Actual enum values:

export enum BookType {
  SCIENCE = 'SCIENCE',
  SCIENCEFICTION = 'SCIENCE_FICTION'
}

openapi-generator version

5.0.0-SNAPSHOT

OpenAPI declaration file content or url

{
  "openapi": "3.0.1",
  "info": {
    "title": "OpenAPI definition",
    "version": "v0"
  },
  "servers": [
    {
      "url": "/"
    }
  ],
  "paths": {
    "/books/{id}": {
      "get": {
        "tags": [
          "controller"
        ],
        "description": "Get book by ID",
        "operationId": "getBookById",
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "string",
              "format": "uuid"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "*/*": {
                "schema": {
                  "$ref": "#/components/schemas/Book"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "Book": {
        "required": [
          "id",
          "type"
        ],
        "type": "object",
        "properties": {
          "id": {
            "type": "string",
            "description": "ID",
            "format": "uuid"
          },
          "type": {
            "type": "string",
            "description": "Book type",
            "enum": [
              "SCIENCE",
              "SCIENCE_FICTION"
            ]
          }
        },
        "description": "Book"
      }
    },
    "securitySchemes": {
      "basicScheme": {
        "type": "http",
        "scheme": "basic"
      }
    }
  }
}

Generation Details

Generator: typescript-axios Config options:

<configOptions>
   <enumPropertyNaming>PascalCase</enumPropertyNaming>
</configOptions>

Steps to reproduce

This issue can be reproduced by using the typescript-axios generator with the OpenAPI declaration & config from above.