Add uv as a required dependency for codegen for early return

[Divyansh-db]

Add uv as a required dependency to ensure code generation as uv is used in one of the post_generation commands make fmt. This ensures that generation fails early on in environments which do not have uv rather then failing post generation.

What changed

Internal changes

Now the codegen checks if uv exists before starting code generation

How is this tested?

N/A

NO_CHANGELOG=true

[github-actions]

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Trigger:
go/deco-tests-run/sdk-py

Inputs:

• PR number: 1395
• Commit SHA: ec78d22908b2bb75f80d5b306ab787a5e23c6970

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