[BUG][typescript-angular] PropertyNames on dictionaries are ignored

Description

If an object has a property that specifies additionalProperties and propertyNames then propertyNames is not taken into account when generating the interface.

openapi-generator version

7.8.0

OpenAPI declaration file content or url

components:
  schema:
    SomeDTO:
      map:
        type: object
        additionalProperties:
          type: array
          items:
            $ref: '#/components/schemas/OtherDTO'
        propertyNames:
          type: string
          enum:
          - FOO
          - BAR

Generation Details

Generated using: openapi-generator-maven-plugin

Configuration:

<typeMappings>
  <typeMapping>DateTime=string</typeMapping>
</typeMappings>

<configOptions>
  <ngVersion>17.3.11</ngVersion>
</configOptions>

Steps to reproduce

Run the generation and check the generated interface

expected output:

interface SomeDTO {
  map: {
    foo: Array<OtherDTO>;
    bar: Array<OtherDTO>;
    [key: string]: Array<OtherDTO>;
  }
}

actual output:

interface SomeDTO {
  map: { [key: string]: Array<OtherDTO>; }
}

Reproduce the issue with the YAML declaration and openapi-generator-maven-plugin configuration, then inspect the generated TypeScript interface for SomeDTO. Compare the output with the expected interface and verify that the propertyNames enum values and the index signature are both represented.