feat(common): add generic for argument metadata

[y-nk]

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?

When using the ArgumentMetadata type in a transform pipe, we can't type metadata?.metatype which always ends up with a as XXX because the type is fixed to Type<any>

What is the new behavior?

Optional generic can be passed to ArgumentMetadata<MyClass> so that we can do:

if (metadata?.metatype) {
  const metatype = new metadata.metatype()
}

and get type safety both in the constructor and instance type

Does this PR introduce a breaking change?

• Yes
• No

[coveralls]

Pull Request Test Coverage Report for Build a4d5f079-e4c7-473a-a3b3-a406892e6719

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 42 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.02%) to 88.934%

---

Files with Coverage Reduction	New Missed Lines	%
packages/core/injector/injector.ts	42	84.27%

Totals
Change from base Build 74b1a9ab-0b2d-47c2-9b96-2e66bcee106c:	0.02%
Covered Lines:	7265
Relevant Lines:	8169

---

💛 - Coveralls

[y-nk]

@Hardanish-Singh is there a reason for not merging 🙏? i can help if needed.

[Hardanish-Singh]

@y-nk you would have to ask the code owners to merge this PR

[y-nk]

@kamilmysliwiec 🙏