Use state 0 frequency for signal experiments

[andrea-pasquale]

Closes #1070

[codecov]

Codecov Report

Attention: Patch coverage is 92.50000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 96.90%. Comparing base (3ef4f92) to head (520d035).

Files with missing lines	Patch %	Lines
src/qibocal/protocols/utils.py	83.33%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              0.2    #1071      +/-   ##
==========================================
- Coverage   96.97%   96.90%   -0.08%     
==========================================
  Files         100      100              
  Lines        8078     8085       +7     
==========================================
+ Hits         7834     7835       +1     
- Misses        244      250       +6     

Flag	Coverage Δ
unittests	96.90% <92.50%> (-0.08%)	⬇️

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

Files with missing lines	Coverage Δ
src/qibocal/calibration/calibration.py	95.68% <100.00%> (+0.07%)	⬆️
...rc/qibocal/protocols/coherence/spin_echo_signal.py	100.00% <100.00%> (ø)
src/qibocal/protocols/coherence/t1_signal.py	98.92% <100.00%> (ø)
src/qibocal/protocols/coherence/t2_signal.py	100.00% <100.00%> (ø)
src/qibocal/protocols/dispersive_shift.py	100.00% <ø> (ø)
src/qibocal/protocols/dispersive_shift_qutrit.py	100.00% <ø> (ø)
...bocal/protocols/flux_dependence/qubit_crosstalk.py	97.01% <100.00%> (+0.02%)	⬆️
...protocols/flux_dependence/qubit_flux_dependence.py	98.26% <100.00%> (ø)
...ocols/flux_dependence/resonator_flux_dependence.py	98.37% <100.00%> (-0.02%)	⬇️
src/qibocal/protocols/qubit_power_spectroscopy.py	100.00% <100.00%> (ø)
... and 11 more

... and 2 files with indirect coverage changes