💡 [REQUEST] - adding a reusable mock HTTP client for unit tests

[GrandinLuc]

Summary

In the new thor package, for the unit tests we are currently using a hardcoded mockHttpClient method on every unit tests so to avoid all that copy/paste this ticket aims to have a MockHttpClient that is light-weight and modulable for all the unit tests current and future.

Basic Example

This is the current mockHttpClient (this one is only for POST requests:
const mockHttpClient = <T>(response: T): FetchHttpClient => { return { post: jest.fn().mockImplementation(() => { return { json: jest.fn().mockImplementation(() => { return response; }) }; }) } as unknown as FetchHttpClient; };