title: withLatestFrom does not emit value
body: <p>I'm trying to block main stream until config is initialized using <code>withLatestFrom</code> operator and secondary stream (which contains info about config state).</p>
  
  <p>Here is my code:</p>
  
  <pre class="lang-js prettyprint-override"><code>@Effect()
  public navigationToActiveRedemptionOffers = this.actions$.ofType(ROUTER_NAVIGATION)
    .filter((action: RouterNavigationAction&lt;RouterStateProjection&gt;) =&gt; {
      return action.payload.event.url.includes('/redemption-offers/list/active');
    })
    .do(() =&gt; console.log('before withLatestFrom'))
    .withLatestFrom(
      this.store.select(selectConfigInitialized)
        .do(initialized =&gt; console.log('before config filter', initialized))
        .filter(initialized =&gt; initialized)
        .do(initialized =&gt; console.log('after config filter', initialized)),
    )
    .do(() =&gt; console.log('after withLatestFrom'))
    .switchMap(data =&gt; {
      const action = data[0] as RouterNavigationAction&lt;RouterStateProjection&gt;;
  
      return [
        new MapListingOptionsAction(action.payload.routerState.queryParams),
        new LoadActiveOffersAction(),
      ];
    });
  </code></pre>
  
  <p>Problem is that second <code>do</code> (after <code>withLatestFrom</code>) block never gets called.
  Log:</p>
  
  <ul>
  <li>before config filter false</li>
  <li>before withLatestFrom</li>
  <li>before config filter true</li>
  <li>after config filter true</li>
  </ul>
  
  <p>Thank you for your suggestions.</p>