fix: fix nullable primitive types defined as list of types (#10388)

[ctyar]

At the moment, Swagger UI doesn't produce a correct Example Value with OpenAPI 3.1.1 definition for a nullable property which is defined as an array of types (e.g., ["null", "string"]).

Description

This PR will change the logic that folds an array of types to ignore null so a better example value would be created.

Motivation and Context

Fixes #10388

How Has This Been Tested?

Tested with the following sample definition:

{
  "openapi": "3.1.1",
  "info": {
    "title": "Playground | v1",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "http://localhost:5150"
    }
  ],
  "paths": {
    "/todos": {
      "post": {
        "tags": [
          "TodoEndpoints"
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/TodoRequest"
              }
            }
          },
          "required": true
        },
        "responses": {
          "201": {
            "description": "Created"
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "NullableOfPriority": {
        "enum": [
          "Low",
          "Medium",
          "High",
          "Critical",
          null
        ]
      },
      "TodoRequest": {
        "required": [
          "description",
          "priority"
        ],
        "type": "object",
        "properties": {
          "description": {
            "type": [
              "null",
              "string"
            ]
          },
          "dueDate": {
            "type": [
              "null",
              "string"
            ],
            "format": "date-time"
          },
          "priority": {
            "$ref": "#/components/schemas/NullableOfPriority"
          },
          "tags": {
            "type": [
              "null",
              "array"
            ],
            "items": {
              "type": "string"
            }
          }
        }
      }
    }
  },
  "tags": [
    {
      "name": "TodoEndpoints"
    }
  ]
}

Checklist

My PR contains...

• No code changes (src/ is unmodified: changes to documentation, CI, metadata, etc.)
• Dependency changes (any modification to dependencies in package.json)
• Bug fixes (non-breaking change which fixes an issue)
• Improvements (misc. changes to existing features)
• Features (non-breaking change which adds functionality)

My changes...

• are breaking changes to a public API (config options, System API, major UI change, etc).
• are breaking changes to a private API (Redux, component props, utility functions, etc.).
• are breaking changes to a developer API (npm script behavior changes, new dev system dependencies, etc).
• are not breaking changes.

Documentation

• My changes do not require a change to the project documentation.
• My changes require a change to the project documentation.
• If yes to above: I have updated the documentation accordingly.

Automated tests

• My changes can not or do not need to be tested.
• My changes can and should be tested by unit and/or integration tests.
• If yes to above: I have added tests to cover my changes.
• If yes to above: I have taken care to cover edge cases in my tests.
• All new and existing tests passed.

[glowcloud]

Hi @ctyar

Thanks for raising this issue and for the PR!

The generated example you provided in the issue is correct, but we think that deprioritising null in favour of other primitive types would be the best.

Your approach here is good, but we cannot ignore null, e.g. in case of type: ["null"]. Please take a look at the code suggestions.

[ctyar]

@glowcloud thank you for your review and the great project
Applied all the feedbacks

[glowcloud]

@ctyar Thanks for the changes, LGTM!