When setting custom client output directory, generated package.json does not include "sideEffects: false"

[boblauer]

Bug description

When you generate the prisma client without specifying a custom path, the package.json at @prisma/client/package.json will specify sideEffects: false.

However, when you specify a custom path in your schema.prisma file, the generated json does not specify sideEffects: false, and so the package will not be tree-shaken from your client-side bundle.

How to reproduce

1. Modify schema.prisma to include output = './some-custom-path' within the generator client section
2. npx prisma generate
3. Navigate to the generated output directory and open package.json
4. See that sideEffects: false is not present

Expected behavior

I would expect the package.json to include sideEffects: false just as it does when not specifying a custom path.

Prisma information

generator client {
  provider      = "prisma-client-js"
  binaryTargets = "native"
  output        = "./../../node_modules/@bug/prisma-client"
}

Environment & setup

• OS: macOS
• Database: PostgreSQL
• Node.js version: 16.3.0

Prisma Version

3.15.2