[feat]patchStateWithImmer

[mzkmnk]

Issue

#9

Content

This function leverages Immer's produce to let you write mutable-looking
changes in the updater callback while actually creating a new, immutable
state object under the hood.

** e.g **

import {signalStore} from "@ngrx/signals";

export const UserSignalStore = signalStore(
  withState<{ name: string, age: number }>({name: 'John', age: 30}),
  withMethods((store) => ({
    editUser: (name: string) => {
      // here
      patchStateWithImmer(store, (state) => {
        state.user.name = name;
      });
    },
  }))
)