build(deps): bump file-type from 16.5.4 to 21.3.1 in /extensions/git (#300597)

* build(deps): bump file-type from 16.5.4 to 21.3.1 in /extensions/git

Bumps [file-type](https://github.com/sindresorhus/file-type) from 16.5.4 to 21.3.1.
- [Release notes](https://github.com/sindresorhus/file-type/releases)
- [Commits](https://github.com/sindresorhus/file-type/compare/v16.5.4...v21.3.1)

---
updated-dependencies:
- dependency-name: file-type
  dependency-version: 21.3.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

* fix(git): update file-type import for v21.x API (#301231)

* Initial plan

* fix: update file-type import for v21.x API changes

Co-authored-by: rzhao271 <[email protected]>

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: rzhao271 <[email protected]>

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Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Raymond Zhao <[email protected]>
Co-authored-by: Copilot <[email protected]>