Revert "Add start_sigma to ADVI (#6096)"

[ricardoV94]

Reverts #6096 due to #6127

Major / Breaking Changes

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Bugfixes / New features

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Docs / Maintenance

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[codecov]

Codecov Report

Merging #6130 (e8ed9b6) into main (c53cd2f) will increase coverage by 0.56%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6130      +/-   ##
==========================================
+ Coverage   91.37%   91.93%   +0.56%     
==========================================
  Files         101      101              
  Lines       20887    20951      +64     
==========================================
+ Hits        19085    19262     +177     
+ Misses       1802     1689     -113     

Impacted Files	Coverage Δ
pymc/variational/approximations.py	87.32% <100.00%> (+32.52%)	⬆️
pymc/variational/inference.py	86.09% <100.00%> (+35.31%)	⬆️
pymc/sampling_jax.py	0.00% <0.00%> (-97.19%)	⬇️
pymc/step_methods/hmc/base_hmc.py	89.76% <0.00%> (-0.79%)	⬇️
pymc/tests/distributions/test_distribution.py	97.83% <0.00%> (ø)
pymc/backends/arviz.py	90.61% <0.00%> (+0.81%)	⬆️
pymc/distributions/distribution.py	96.00% <0.00%> (+1.77%)	⬆️
pymc/tests/distributions/test_timeseries.py	95.78% <0.00%> (+2.03%)	⬆️
pymc/variational/updates.py	92.11% <0.00%> (+3.44%)	⬆️
pymc/initial_point.py	100.00% <0.00%> (+5.88%)	⬆️
... and 8 more