refactor: removes createReducer

libs/utils/rx/src/index.ts

 export { httpRetryBackoff, HttpRetryBackoffConfig } from './lib/http-backoff';
-export { createReducer } from './lib/reducer-utils';

libs/utils/rx/src/lib/reducer-utils.spec.ts

-import { createReducer } from '..';
-
-describe('reducer utils', () => {
-  describe('createReducer', () => {
-    it('should create reducer correctly', () => {
-      const result = createReducer({}, {});
-      expect(result instanceof Function).toBe(true);
-      expect(result({ s: 's' }, {})).toEqual({ s: 's' });
-    });
-  });
-});

libs/utils/rx/src/lib/reducer-utils.ts

-/**
- * @deprecated use ngrx reducer creators instead
- *
- */
-export function createReducer(iState, handlers): (state, action) => any {
-  return (state = iState, action) => {
-    return handlers.hasOwnProperty(action.type) ? handlers[action.type](state, action) : state;
-  };
-}