fix(tsd): correct expectError usage for newUser._id #15766

[THE-Amrit-mahto-05]

Fix TypeScript type error test for newUser._id in tsd tests.

The existing test used invalid syntax:

expectError((_id: number) = newUser._id)

This has been replaced with the correct callback syntax:

expectError(() => { const _id: number = newUser._id; });

This ensures that TypeScript correctly flags assignments of ObjectId to number while keeping the tsd tests valid.

Before:
expectError((_id: number) = newUser._id);

After:
expectError(() => {
const _id: number = newUser._id;
});

The previous syntax caused confusion and TypeScript would not correctly catch the type error. This fix aligns the test with valid tsd usage.

[THE-Amrit-mahto-05]

@vkarpov15 please review my PR