[BUG][csharp-netcore] fail to resolve references to enum types with camlCase names

Created by: fujieda

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Foo class generated from the following declaration has a comparison between null and the property 'Bar' of which type is EnumA.

openapi: 3.0.0
info:
  title: enum ref test
  version: 1.0.0
paths: {}
components:
  schemas:
    foo:
      type: object
      properties:
        bar:
          $ref: '#/components/schemas/enumA'
    enumA:
      type: string
      enum:
        - "a"
        - "b"

public bool Equals(Foo input)
{
    if (input == null)
    {
        return false;
    }
    return 
        (
            this.Bar == input.Bar ||
            (this.Bar != null &&
            this.Bar.Equals(input.Bar))
        );
}

The code generator must omit the comparison because EnumA is a value type. The generator seems to fail to resolve the ref #/components/schemas/enumA.

If I change the key of the enum declarlation to EnumA as follows, the result doesn't have the comparison.

openapi: 3.0.0
info:
  title: enum ref test
  version: 1.0.0
paths: {}
components:
  schemas:
    foo:
      type: object
      properties:
        bar:
          $ref: '#/components/schemas/EnumA'
    EnumA:
      type: string
      enum:
        - "a"
        - "b"

public bool Equals(Foo input)
{
    if (input == null)
    {
        return false;
    }
    return 
        (
            this.Bar == input.Bar ||
            this.Bar.Equals(input.Bar)
        );
}

openapi-generator version

openapi-generator-cli-6.1.0-20220820.044513-79.jar

Steps to reproduce

Just run the following command. `simple.yml' contains the above declarations.

java -jar openapi-generator-cli-6.1.0-20220820.044513-79.jar generate -g csharp-netcore -i simple.yml

Suggest a fix

I will submit a PR to fix this.