types: relax model<T> type signature to allow any schema

[vkarpov15]

Fix #15681

Summary

Something in 8.19.0 release started causing the following script to OOM crash:

import mongoose from "mongoose";

function getMongooseModel<T>(resName: string): mongoose.Model<T> {
  if (mongoose.models[resName]) {
    return mongoose.models[resName];
  }

  const schema = new mongoose.Schema({
    example: String,
  });

  return mongoose.model<T>(resName, schema);
}

type Example = {
  name: string;
};

const Model = getMongooseModel<Example>("Example");

I haven't been able to figure out exactly what, but there are two easy fixes:

1. Update user code to do const schema = new mongoose.Schema<T>(...)
2. Allow model<T> to take in Schema<any> as opposed to Schema<T>

(2) seems reasonable to do, although we will also suggest (1). These fixes unfortunately seem to be exclusive - applying (2) makes (1) fail with OOM :(

Examples

[Copilot]

Pull Request Overview

This PR fixes a type signature issue in Mongoose's model<T> function that was causing OOM crashes in TypeScript when using generic models with untyped schemas. The change relaxes the type constraints to accept Schema<any> instead of requiring Schema<T>, allowing developers to create generic model functions without needing to explicitly type their schemas.

Key changes:

• Relaxed type signature for model<T> to accept any schema type
• Added test case demonstrating the previously problematic usage pattern

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