fix(common): import of file-type to resolve validation mismatch

[Yasir-Rafique]

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?

The FileTypeValidator dynamically imports the file-type package using loadEsm. This approach can lead to loading the wrong version of file-type if another package (like jimp) installs a different version that gets hoisted, resulting in inconsistent or incorrect file validation results.

This was reported in #15270, where developers were encountering issues like:
Validation failed (current file type is application/octet-stream, expected type is ...)

Issue Number: 15270

What is the new behavior?

• Replaced dynamic import using loadEsm with a direct static import:
  import { fileTypeFromBuffer } from 'file-type';

Does this PR introduce a breaking change?

• Yes
• No

Other information

This fix ensures more predictable and stable validation behavior in file uploads by removing reliance on hoisted or mismatched file-type versions. It improves compatibility and aligns the package with modern best practices for peer dependency handling.

[coveralls]

Pull Request Test Coverage Report for Build 65d65112-245d-4e15-88dc-e384fa504be2

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 88.918%

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Totals
Change from base Build bc91b2b9-9bd0-4dac-a3ac-a0d262be1578:	0.0%
Covered Lines:	7197
Relevant Lines:	8094

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💛 - Coveralls