Remove op.is_hermitian check in expval, counts, sample to allow jit tracing

[Qottmann]

Solves #5505 and also fixes the same issue in catalyst

tldr: The is_hermitian check is breaking jit-compilation

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.66%. Comparing base (b2b0c36) to head (96969b5).
Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5506      +/-   ##
==========================================
- Coverage   99.67%   99.66%   -0.01%     
==========================================
  Files         404      404              
  Lines       37833    37555     -278     
==========================================
- Hits        37709    37430     -279     
- Misses        124      125       +1     

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[rmoyard]

Thanks for the change!