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.

const currentScale = this._currentScale;
    const currentScaleValue = this._currentScaleValue;
    const normalizedScaleValue =
      parseFloat(currentScaleValue) === currentScale
        ? Math.round(currentScale * 10000) / 100
        : currentScaleValue;
    const pageNumber = firstPage.id;
    let pdfOpenParams = "#page=" + pageNumber;
    pdfOpenParams += "&zoom=" + normalizedScaleValue;
    const currentPageView = this._pages[pageNumber - 1];
    const container = this.container;
    const topLeft = currentPageView.getPagePoint(
      container.scrollLeft - firstPage.x,
      container.scrollTop - firstPage.y
    );
    const intLeft = Math.round(topLeft[0]);
    const intTop = Math.round(topLeft[1]);
    pdfOpenParams += "," + intLeft + "," + intTop;
    this._location = {
      pageNumber,
      scale: normalizedScaleValue,
      top: intTop,
      left: intLeft,
      rotation: this._pagesRotation,
      pdfOpenParams,
    };
  }
  update() {