Allow transforms to work with multiple-valued nodes

[ricardoV94]

This showed up in pymc-devs/pymc-extras#91

https://github.com/pymc-devs/pymc-experimental/blob/5a01d4fc5d58fc1abb52f13fcb5cd4e8b32292ba/pymc_experimental/tests/test_marginal_model.py#L349-L368

Major / Breaking Changes

• ...

Bugfixes / New features

• Allow transforms for multiple_valued RVs

Docs / Maintenance

• ...

[codecov]

Codecov Report

Merging #6341 (3b5b84b) into main (ddc6b65) will decrease coverage by 2.06%.
The diff coverage is 98.80%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6341      +/-   ##
==========================================
- Coverage   94.71%   92.64%   -2.07%     
==========================================
  Files         132      132              
  Lines       26695    26751      +56     
==========================================
- Hits        25284    24784     -500     
- Misses       1411     1967     +556     

Impacted Files	Coverage Δ
pymc/logprob/transforms.py	99.05% <97.82%> (-0.28%)	⬇️
pymc/tests/logprob/test_transforms.py	99.37% <100.00%> (+0.08%)	⬆️
pymc/tests/variational/test_updates.py	0.00% <0.00%> (-100.00%)	⬇️
pymc/tests/backends/test_arviz.py	0.00% <0.00%> (-99.03%)	⬇️
pymc/variational/updates.py	37.93% <0.00%> (-54.19%)	⬇️
pymc/backends/arviz.py	87.76% <0.00%> (-2.96%)	⬇️
pymc/model.py	89.62% <0.00%> (-0.14%)	⬇️

[michaelosthege]

I'm proud to have found something.

I get the idea and trust your test.