Inconsistent readonly usage

[peterreisz]

Minimal reproduction of the bug/regression with instructions:

Here we have readonly modifier before the ActionCreator[]:

platform/modules/store/src/reducer_creator.ts

Lines 24 to 26 in 7515e36

	export interface OnReducer<State, Creators extends readonly ActionCreator[]> {
	(state: State, action: ActionType<Creators[number]>): State;
	}

But here we don't:

platform/modules/store/src/reducer_creator.ts

Lines 105 to 108 in 7515e36

	export function createReducer<S, A extends Action = Action>(
	initialState: S,
	...ons: ReducerTypes<S, ActionCreator[]>[]
	): ActionReducer<S, A> {

Expected behavior:

Be consistent, use readonly in both places.

Versions of NgRx, Angular, Node, affected browser(s) and operating system(s):

ngrx store version: 12.1.0

Other information:

In my project I have several reducer function extracted to a variable and a linter rule demands that I specify the type for them.
If I want to satisfy the linter, the inconsistent readonly usage results non compiling code.

I would be willing to submit a PR to fix this issue

[x] Yes (Assistance is provided if you need help submitting a pull request)
[ ] No

[timdeschryver]

This seems like a reasonable change, feel free to create a Pull Request.