Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version:
Firefox/Chrome, latest version
- Operating system and its version:
Linux,Windows,mac
- PDF.js version:
v2.12.313
- Is a browser extension:
no

Steps to reproduce the problem:
1. create a custom viewer with 
```
async function getViewer() {
const viewer = await import(/* webpackChunkName: 'pdfviewer' */ 'pdfjs-dist/web/pdf_viewer');
const eventBus = new viewer.EventBus();
return viewer.PDFSinglePageViewer({
        container,
        eventBus,
        useOnlyCssZoom: USE_ONLY_CSS_ZOOM,
        // We can enable text/annotations layers, if needed
        textLayerFactory: new viewer.DefaultTextLayerFactory(),
        annotationLayerFactory: new viewer.DefaultAnnotationLayerFactory(),
        // textLayerMode: TextLayerMode.ENABLE,
        // currently the SVG renderer is not supported
        // and it has problems with telekom documents
        // so it will be disabled until it is feature complete
        // renderer: 'svg'
    });
}
```
2. console prints an error:
```
Unable to get page for page view TypeError: this.linkService._cachedPageNumber is not a function
    ensurePdfPageLoaded_fn base_viewer.js:1502
```
    
Looks like the problem is `IPDFLinkService` which is actually using the default one `this.linkService = options.linkService || new SimpleLinkService();` which does not have this function. of course we can use `PDFLinkService` which will probably work.

state.pages.length = 0;
    if (this._spreadMode === SpreadMode.NONE) {
      
      const pageView = this._pages[pageNumber - 1];
      if (this.isInPresentationMode) {
        const spread = document.createElement("div");
        spread.className = "spread";
        const dummyPage = document.createElement("div");
        dummyPage.className = "dummyPage";
        dummyPage.style.height = `${this.container.clientHeight}px`;
        spread.appendChild(dummyPage);
        spread.appendChild(pageView.div);
        viewer.appendChild(spread);
      } else {
        viewer.appendChild(pageView.div);
      }
      state.pages.push(pageView);
    } else {
      const pageIndexSet = new Set(),
        parity = this._spreadMode - 1;
      
      if (pageNumber % 2 !== parity) {
        
        pageIndexSet.add(pageNumber - 1);
        pageIndexSet.add(pageNumber);
      } else {
        
        pageIndexSet.add(pageNumber - 2);
        pageIndexSet.add(pageNumber - 1);