Omit redundant parent ID validation

[nicodevs]

Since #725, we can use meta.parent to generate routes with nested model binding. For example, this draft:

controllers:
  Comment:
    resource: api
    meta:
      parent: post

... generates the following routes:

  GET|HEAD        api/posts/{post}/comments
  POST            api/posts/{post}/comments
  GET|HEAD        api/posts/{post}/comments/{comment}
  PUT|PATCH       api/posts/{post}/comments/{comment}
  DELETE          api/posts/{post}/comments/{comment}

Laravel automatically resolves the Post model matching the provided {post} ID or returns a 404 if not found. For this reason, receiving and validating post_id in the FormRequest for these routes is redundant.

This PR removes the generation of form requests validation rules for columns named after the controller meta.parent plus the _id suffix (e.g., post_id).

Before and after

Validation Rules Before:

return [
    'body' => ['required', 'string'],
    'post_id' => ['required', 'integer', 'exists:posts,id'],
];

Validation Rules After:

return [
    'body' => ['required', 'string'],
];

Testing

This PR includes a test to verify the generated form request for a controller with a parent. All existing tests remain unchanged and are passing, ensuring form requests are correctly generated in all other scenarios.