Enable dompurify trusted types

[Top-Cat]

Add configuration option RETURN_TRUSTED_TYPE to DomPurify setup (https://github.com/cure53/DOMPurify?tab=readme-ov-file#what-about-dompurify-and-trusted-types)

Description

dangerouslySetInnerHTML will support this type automatically in place of a string.
I don't entirely understand why OAS3 trims the html and the base component doesn't but for now I've chosen to avoid updating a load of expected test values. Happy to change this if desired.

Motivation and Context

This allows enabling require-trusted-types-for in CSP to reduce XSS attack surface.

How Has This Been Tested?

Tested local dev server with both the default and an oas3 api (https://petstore3.swagger.io/api/v3/openapi.json)

Screenshots (if appropriate):

(Looks the same as before)

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.

There are existing tests covering markdown rendering