[Bug] replaceImportPath incorrectly determines import paths from external modules

[IodizedGabe]

I'm submitting a...

[ ] Regression 
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

Using an enum from a separate module for a DTO class field results in the transpiled code under the _OPENAPI_METADATA_FACTORY property to be incorrect.

Expected behavior

Previously, in 4.8.0, this would reference the expected import path starting from node_modules.

This appears to have been introduced in: #1318. Previously, this logic would fall into the else block and have its import path be determined that way. Because the path here is technically resolvable, it doesn't raise an error and gets saved as-is.

Minimal reproduction of the problem with instructions

Example minimal repo: https://github.com/IodizedGabe/nestjs-swagger-incorrect-import

Steps:

1. Run yarn build
2. Open dist/scope.dto.js

The enum field will reference the local path to a given module, and not the expected import path.

What is the motivation / use case for changing the behavior?

I would like to continue using enums from shared packages across my services.

Environment

Nest version: 

        "@nestjs/common": "7.6.18",
        "@nestjs/config": "0.6.3",
        "@nestjs/core": "7.6.18",
        "@nestjs/passport": "7.1.5",
        "@nestjs/swagger": "4.8.1",
 
For Tooling issues:
- Node version: v12.20.2 
- Platform:  Mac/Linux

Others:

"typescript": "4.3.4",

[kamilmysliwiec]

Fixed in 4.8.2

[IodizedGabe]

Thanks!