[BUG] Order of securitySchemes not respected

Created by: gcatanese

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?
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Description

The original order of the securitySchemes is lost during the code generation and replaced with an alphabetical order.

When parsing the following OpenAPI file the outcome is a list of List<CodegenSecurity> sorted alphabetically, in this case [api_key, petstore_auth]

  securitySchemes:
    petstore_auth:
      type: oauth2
      flows:
        implicit:
          authorizationUrl: 'http://petstore.swagger.io/api/oauth/dialog'
          scopes:
            'write:pets': modify pets in your account
            'read:pets': read your pets
    api_key:
      type: apiKey
      name: api_key
      in: header

The code generation should not alter the order from the OpenAPI specs (this order is relevant for tools and applications that work with the securityScheme).

The expected output is aList<CodegenSecurity> with the original order[petstore_auth, api_key]

openapi-generator version

Found on 6.3.0-SNAPSHOT.

Generation Details

It can be reproduced with an OpenAPI specs defining multiple securitySchemes, see DefaultCodegenTest.testOauthMultipleFlows