add nan handling in diagnostics

[janfb]

fixes #1345 by adding nan and inf handling at the beginning of sbc, tarp and lc2st.

[codecov]

Codecov Report

Attention: Patch coverage is 78.57143% with 3 lines in your changes missing coverage. Please review.

Project coverage is 78.44%. Comparing base (d3f22b5) to head (c97f37d).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
sbi/diagnostics/tarp.py	50.00%	1 Missing ⚠️
sbi/utils/diagnostics_utils.py	85.71%	1 Missing ⚠️
sbi/utils/sbiutils.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1359       +/-   ##
===========================================
- Coverage   89.40%   78.44%   -10.97%     
===========================================
  Files         118      118               
  Lines        8715     8779       +64     
===========================================
- Hits         7792     6887      -905     
- Misses        923     1892      +969     

Flag	Coverage Δ
unittests	78.44% <78.57%> (-10.97%)	⬇️

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

Files with missing lines	Coverage Δ
sbi/diagnostics/lc2st.py	96.01% <100.00%> (+0.06%)	⬆️
sbi/diagnostics/sbc.py	95.77% <100.00%> (+0.06%)	⬆️
sbi/diagnostics/tarp.py	80.95% <50.00%> (-16.61%)	⬇️
sbi/utils/diagnostics_utils.py	97.36% <85.71%> (-2.64%)	⬇️
sbi/utils/sbiutils.py	78.11% <0.00%> (-8.68%)	⬇️

... and 30 files with indirect coverage changes

[manuelgloeckler]

Looks great :)