PdfViewer remains blank / downloads pdf in background (Firefox)

**Describe the bug**

When we are trying to display our pdf document using the `` component, it just shows a blank iframe but downloads the pdf in the background without a pdf extension, just named `pdf`.

**To Reproduce**
Steps to reproduce the behavior including code snippet (if applies):

There aren't any weird steps we are taking, we aren't doing anything exotic per se.

This is how we render our document:

```
return (

**Expected behavior**
That PdfViewer shows the PDF instead of download it in the background.

**Desktop (please complete the following information):**
- OS: MacOS
- Browser Firefox v88
- React-pdf version 2.0.8