feat(pdfjs): upgrade pdf.js to 4.3.136

[ahorowitz123]

• Version 4 and greater use mjs files. Added support across the code base for this file type
• Updated pdf.js upgrade script
• Use legacy version of app to avoid errors due to the use of promise.withResolvers which was only recently supported by modern browsers
• Removed manual patches to new pdf.js versions which are no longer needed
• Added manual patch to fix a z-index issue that was conflicting with box-annotations and cause the first link on a pdf to be unaccessible. The issue here results from this code applying an increasing z index to each annotation layer. This causes the first annotation layer to be 0. When you are in region drawing mode, the box-annotations code applies a overlapping div over the whole pdf which sets user events to none. This div also has a z index of 0. When you have sibling divs with the same index, the div which is last in the DOM gets precedence. By ensuring that the z index of the annotation layer begins at 1, we can avoid this collision.
• Removed support for IE11
• Code has been manually tested with entire preview regression folder

Comparison of bundle sizes: Previous version

New version

[ahorowitz123]

We should figure out what impact this change is going to have on performance, especially if the new viewer assets are significantly larger than the old ones.

I've found this difficult to test in dev due to the large fluctuations in loading times due to dev infrastructure. I think we'll get a better idea in staging

[bfoxx1906]

Can we update the description to explain the external link fix with why it was necessary and how the fix works. It'll be helpful for folks down the road to understand why we did this and to be able to tell if we still need it or not.