PDF READER - increase max zoom level

Summary

Just tested the built-in PDF-reader. My impression is that the max zoom level is not sufficient to read random PDF-files. Often PDF-files have really small font size. Many average users may would like to increase the size of PDF documents in order to facilitate readability. Please see screenshots below, they are taken with max zoom level.

I already notified the same issue for the previous PDF app used (#578 (closed)) but I believe the max zoom level for the current app is not sufficient either.

Relevant screenshots