fix(plugin): ensure open-api docs generation for types named with Promise or Observable

[jinyongp]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

I've encountered an issue with NestJS Swagger where automatic API documentation generation does not properly handle types that include the Promise or Observable keywords. This occurs when using @Body(), @Query(), or return types in controllers that are intended to be documented by Swagger.

Issue Number: N/A

What is the new behavior?

Types that include Promise or Observable should be accurately reflected in the Swagger documentation.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[kamilmysliwiec]

lgtm