RB fix U3

[Jacfomg]

Fixes an issue regarding how Qibo handles U3 parameters for the RB

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.
• Compatibility with Qibo modules (Please edit this section if the current pull request is not compatible with the following branches).
  • Qibo: master
  • Qibolab: main
  • Qibolab_platforms_qrc: main

[igres26]

This should fix the issue.

KEEP IN MIND that this is a small patch, and that we should also look into the real issue in the u3 decomposition formula so that it takes into account the determinant of the gate it is trying to decompose.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.15%. Comparing base (1ff6329) to head (7d33c5a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #730      +/-   ##
==========================================
- Coverage   97.19%   97.15%   -0.04%     
==========================================
  Files         108      108              
  Lines        7601     7601              
==========================================
- Hits         7388     7385       -3     
- Misses        213      216       +3     

Flag	Coverage Δ
unittests	97.15% <ø> (-0.04%)	⬇️

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Files	Coverage Δ
.../characterization/randomized_benchmarking/utils.py	100.00% <ø> (ø)

... and 1 file with indirect coverage changes