Add a flag to error when an uninitialized function is called

### 🔍 Search Terms

uninitialized function - uninitialized - uninitialized function call

### ✅ Viability Checklist

- [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code
- [x] This wouldn't change the runtime behavior of existing JavaScript code
- [x] This could be implemented without emitting different JS based on the types of the expressions
- [x] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
- [x] This isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
- [x] This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

### ⭐ Suggestion

This is a request to add a new configuration flag that makes typescript error when an uninitialized **function** is called within the same scope

[This](https://github.com/microsoft/TypeScript/issues/56827#issuecomment-1863251126) is a comment made by @RyanCavanaugh on a similar topic (using an uninitialized variable) for why an error is not thrown by typescript in the case of using an uninitialized variable (not calling a function)

There are more comments on this topic

### But the same argument of why function parameters assignment is contra-variant applies to why throw an error when an uninitialized function is called. Typescript doesn't know if it will surely error but it prevents it anyway

### 📃 Motivating Example

The below is a case of a runtime error thrown by calling an uninitialized variable which typescript didn't prevent

https://www.typescriptlang.org/play/?#code/GYVwdgxgLglg9mABAMXBAjIgFKSAubASgF4A+ANzhgBNCBvAKEWcVwi0MQHovEoALGAGc+-AE5wA7iICGiMeFgBbAKaIVYiWKYsxKqCDFI65GQBsQKggCYAvg3sM2sBIgDm+gHIrJqSEURGFnl9QyQORDJECAQhODMVADozODcsAANvXzR0wgcGBh4YsCEoQNMLFVtIlDR0LDAfPwhOHnUADwAHFWgVakQAIxV+GXJ4MQIBYVEJaUQ5KABPbqEIMRhOso0tRE69chUwWDA3eUUYVXVNODEhBmb6jjI6REbsyAjbVt5wFS6eqB9QbDUbjSaCETUOAqIRgADkZQEs3mfGWMLWGy21zEiEkggg-EQCRk1BEUDgKIURwuam2NwKxVKryaaBqHigWWaHCAA

### 💻 Use Cases

1. What do you want to use this for? **Preventing runtime errors**
2. What shortcomings exist with current approaches? **none**
3. What workarounds are you using in the meantime?

Start by reviewing the motivating TypeScript Playground example and the linked discussion in issue #56827 about uninitialized variables. Define what the new configuration flag should diagnose for same-scope uninitialized function calls, and consider the stated constraints that it must not change emitted JavaScript or existing runtime behavior.

Written by the indexing model from the issue text.