Pseudodata test uses theory 53

[Zaharid]

This failure

https://github.com/NNPDF/nnpdf/runs/4032474811?check_suite_focus=true

looks like some test is wanting to download theory 53, which really should not happen.

[siranipour]

The reason for this is that

nnpdf/validphys2/src/validphys/tests/conftest.py

Line 48 in 817f9aa

FIT = "191015-mw-001_for_testing"

was run with theory 53

[scarlehoff]

This is fixed by PR #1440