Add tutorials test

[janfb]

• add test that executes all tutorials
• add corresponding fixes due to API changes

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 76.82%. Comparing base (b3254ed) to head (f1944e8).
Report is 11 commits behind head on main.

Files	Patch %	Lines
sbi/inference/base.py	25.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1232      +/-   ##
==========================================
- Coverage   85.44%   76.82%   -8.63%     
==========================================
  Files         101      101              
  Lines        7941     7947       +6     
==========================================
- Hits         6785     6105     -680     
- Misses       1156     1842     +686     

Flag	Coverage Δ
unittests	76.82% <40.00%> (-8.63%)	⬇️

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Files	Coverage Δ
sbi/analysis/__init__.py	100.00% <ø> (ø)
sbi/analysis/plot.py	68.20% <100.00%> (-2.32%)	⬇️
sbi/inference/posteriors/importance_posterior.py	86.15% <ø> (ø)
sbi/inference/base.py	86.91% <25.00%> (-2.40%)	⬇️

... and 24 files with indirect coverage changes