[BUG][Elm] invalid code is generated for array of enum strings

Description

When generating Elm code with a schema that has an array property with items of type string enum, the generated code is invalid. The encoder tries to encode the enum as an integer, which is incorrect. The function it tries to reference does not exist.

openapi-generator version

7.16.0

OpenAPI declaration file content or url

{
  "openapi" : "3.0.1",
  "info" : {
    "title" : "OpenAPI definition",
    "version" : "v0"
  },
  "servers" : [ {
    "url" : "http://127.0.0.1:4000",
    "description" : "Generated server url"
  } ],
  "paths": {},
  "components" : {
    "schemas" : {
      "TestObject" : {
        "type" : "object",
        "properties" : {
          "body" : {
            "type" : "array",
            "items": {
              "type" : "string",
              "enum" : [ "ENUM_FIRST", "ENUM_SECOND", "ENUM_THIRD" ]
            }
          }
        }
      }
    }
  }
}

Generation Details

npx @openapitools/openapi-generator-cli generate -i openapi.json -g elm -o elm

Steps to reproduce

Run the generated command, see that the generated file contains:

encodeTestObjectBody : TestObjectBody -> Json.Encode.Value
encodeTestObjectBody =
    Json.Encode.int << intFromTestObjectBody

while it should be

encodeTestObjectBody : TestObjectBody -> Json.Encode.Value
encodeTestObjectBody =
    Json.Encode.string << stringFromTestObjectBody

Suggest a fix

See above. Fix is to correctly interpret the enum as a string.

Reproduce the issue with the supplied OpenAPI declaration and the npx @openapitools/openapi-generator-cli generate -i openapi.json -g elm -o elm command. Inspect the generated encodeTestObjectBody output and verify that the array of string enum values uses Json.Encode.string and the generated Elm code is valid.