JabRef version 5.1 on OpenSUSE Leap 15.2

• Mandatory: I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

Steps to reproduce the behavior:

1. Have the conference paper Map2Check Using LLVM and KLEE in your library
2. "Search full text documents online"
3. JabRef downloads a PDF of the whole conference proceedings instead of just the paper

I looked through the code a bit and it seems like the DoiResolution fetcher has a higher trust value (TrustLevel.SOURCE) than the SpringerLink fetcher (TrustLevel.PUBLISHER). Whereas the SpringerLink fetcher gets the correct link to the paper PDF, the DoiResolution fetcher selects the wrong PDF link from the Springer website.