TS compilation fails with noUncheckedIndexedAccess set to true

**Describe the Bug**
Generated file `helpers.ts` in invalid for TypeScript setups with `"noUncheckedIndexedAccess": true` in their `tsconfig.json`.
This is an issue if the code is generated outside of `node_modules`, for example with the config:
```
generator typegraphql {
provider = "typegraphql-prisma"
output = "../generated/type-graphql"
}
```

The issue is due to an unchecked index access:
```
generated/type-graphql/helpers.ts:27:22 - error TS2488: Type '[string, any] | undefined' must have a '[Symbol.iterator]()' method that returns an iterator.

27 const [[key, { value }]] = Object.entries(argument);
```

**To Reproduce**
* Add `"noUncheckedIndexedAccess": true` to your `tsconfig.json`
* Add a custom output to your generator config

**Expected Behavior**
TS should be able to compile correctly

**Environment (please complete the following information):**

- OS: MacOS 15.6.1
- Node 22.18.0
- `typegraphql-prisma` 0.28.0
- Prisma version 5.22.0
- TypeScript version 5.9.2

**Additional Context**
Opening a PR to solve this issue.

Start with generated/type-graphql/helpers.ts at line 27 and reproduce the failure using noUncheckedIndexedAccess in tsconfig.json with a custom generator output. Verify the generated helpers.ts compiles successfully under the reported TypeScript setup without the TS2488 error.

Written by the indexing model from the issue text.