types: remove logic that omits timestamps when virtuals, methods, etc. options set

[vkarpov15]

Fix #12807

Summary

Looks like the original issue from #12807 just went away, either due to a recent TypeScript release or some other fix we did. This fix would have still worked in 8.17.0, but not 8.16.0

Examples

[Copilot]

Pull Request Overview

This PR removes the TypeScript logic that excluded timestamp inference when virtuals, methods, or statics options were set in Mongoose schemas. The change fixes issue #12807 by enabling proper type inference for schemas with timestamps alongside other schema options.

• Updates test to verify timestamp inference works with methods
• Removes outdated documentation about timestamp inference limitations
• Adds verification that both model properties and methods maintain correct typing

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
test/types/schema.test.ts	Updates type inference test to verify timestamps work with methods and adds model instantiation test
docs/typescript/schemas.md	Removes documentation about timestamp inference limitation with methods/virtuals/statics

[hasezoey]

LGTM