Fix zuko kwargs

[janfb]

The slow test tests/linearGaussian_snle_test.py::test_c2st_and_map_snl_on_linearGaussian_different is failing because we are passing nflows related kwargs to the zuko flow builder.

Excluding those kwargs fixes the problem.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.24%. Comparing base (7be2115) to head (9918213).
Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1130      +/-   ##
==========================================
- Coverage   85.45%   77.24%   -8.22%     
==========================================
  Files          90       89       -1     
  Lines        6612     6617       +5     
==========================================
- Hits         5650     5111     -539     
- Misses        962     1506     +544     

Flag	Coverage Δ
unittests	77.24% <100.00%> (-8.22%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
sbi/neural_nets/flow.py	93.04% <100.00%> (-5.58%)	⬇️

... and 23 files with indirect coverage changes

[janfb]

slow test are passing, except the PyMC stuff, see #1129

[michaeldeistler]

thanks!