"@azure/functions-core" can't be resolved by bundlers

When using a bundler such as `esbuild`, bundling `@azure/functions` causes this error:

```js
✘ [ERROR] Could not resolve "@azure/functions-core"

node_modules/@azure/functions/dist/azure-functions.js:1657:25:
1657 │ module.exports = require("@azure/functions-core");
```

> NOTE: bundling with `ncc` has same problem but `esbuild` emits a better error message

There is no published npm module `@azure/functions-core`.

I see that there is a path mapping in `tsconfig.json`, perhaps it's a shim for old or MS internal code?

In any case, this breaks bundlers and is very annoying. Can we please get this removed from the tsconfig and just use the correct internal import reference?