improvement: generate default oauth2RedirectUrl based on page location

[astellingwerf]

… including the path (an omission of #5085)

Description

The previous improvement (#5085) assumed that the Swagger UI was hosted at the root path.

Motivation and Context

Though this might be true for some situation, it's likely to be false for many deployments. By involving the path into the oauth2RedirectUrl, the Oauth2 flow would typically work more often.

How Has This Been Tested?

I initally wrote a rewriting filter that applied the fix to a running deployment of Spring Boot. When that worked, I applied the same fix to the code, and wrote 3 additional tests that prove the fix.

Screenshots (if appropriate):

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.

[tim-lai]

@astellingwerf PR merged! Thanks for the contribution!

Also, thanks @mitasov-ra for the review!

[mitasov-ra]

@tim-lai please close related issues: #5384 and #6591