Fix Categorical and Multinomial bugs

[ricardoV94]

Closes #5514

Major / Breaking Changes

• ...

Bugfixes / New features

• Fix bug when passing a list or tuple of variables as the p parameter of Categorical and Multinomial distributions

Docs / Maintenance

• ...

[codecov]

Codecov Report

Merging #6265 (1b5ad99) into main (48664c0) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6265   +/-   ##
=======================================
  Coverage   94.19%   94.19%           
=======================================
  Files         102      102           
  Lines       21477    21487   +10     
=======================================
+ Hits        20230    20240   +10     
  Misses       1247     1247           

Impacted Files	Coverage Δ
pymc/distributions/discrete.py	99.22% <100.00%> (+<0.01%)	⬆️
pymc/distributions/multivariate.py	92.28% <100.00%> (+0.02%)	⬆️
pymc/tests/distributions/test_discrete.py	98.88% <100.00%> (+<0.01%)	⬆️
pymc/tests/distributions/test_mixture.py	99.35% <100.00%> (ø)
pymc/tests/distributions/test_multivariate.py	99.45% <100.00%> (+<0.01%)	⬆️

[Armavica]

Thank you for fixing this bug! This seems fine to me. It works for my issue and also for the slightly more complex model which was behind.