[BUG] java native: oauth files not being generated

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

oauth files not generated for java native http client

openapi-generator version

5.0.1

OpenAPI declaration file content or url

components:
  securitySchemes:
    bpay_auth:
      type: oauth2
      flows:
        clientCredentials:
          tokenUrl: https://sandbox.api.bpaygroup.com.au/oauth/token
          scopes:
            read:validate-payment: BPAY payment validation API

(for YAML code) or

# native http client supported in java 11
generatorName: java
outputDir: samples/client/bpay/java/native
library: native
additionalProperties:
  artifactId: bpay
  hideGenerationTimestamp: "true"
  dateLibrary: "java8"
  httpUserAgent: "Shane-Bpay-Java/1.0.0"
  modelPackage: "com.shane.bpay.models"
  apiPackage: "com.shane.bpay.api"
  groupId: "com.shane"

Generation Details

    $SWAGGER_CMD generate \
        --input-spec "./bpay-oas.yaml" \
        -g "$1" \
        --config "./swagger-config/config-$1.yaml"

Steps to reproduce

If i change to another client like the default, then i see the oauth files

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/6284

Suggest a fix

Reproduce the report with bpay-oas.yaml and swagger-config/config-$1.yaml, using generatorName java and library native, then compare its output with the default client. Trace the Java native-library generation path for OAuth files; done means the native client generates the expected OAuth files for the provided security scheme and no longer differs from the default client in this respect.