fix: correct ApiParam type as in: path

[thiagotognoli]

PR Checklist

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• 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)
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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?

Issue Number: #3061

What is the new behavior?

Class ApiProperties must be mapped as in: "path" when used in type of ApiParam

Does this PR introduce a breaking change?

• Yes
• No

Other information

[kamilmysliwiec]

lgtm