Increase support for batched multivariate distributions

The logp of several multivariate distributions does not work (or is not tested) for arbitrarily batched dimensions. Some cases I could confirm include:

• MvNormal - #6897
• MvStudentT #6897
• KroneckerNormal
• MatrixNormal
• LKJCorr
• LKJCholeskyCov
• StickBreakingWeights (alpha) #6042
• Wishart (may be fine to ignore) #8246
• CARRV (maybe better to leave this one as is)

Reproducible code:

size = (4, 3)
pm.logp(pm.MvNormal.dist(mu=np.ones(2), cov=np.eye(2), size=size), np.ones((*size, 2)))
# ValueError: Invalid dimension for value: 3
pm.logp(pm.MvStudentT.dist(nu=3, mu=np.ones(2), cov=np.eye(2), size=size), np.ones((*size, 2)))
# ValueError: Invalid dimension for value: 3

Distributions that already support (and have tests for) arbitrary shapes

• Dirichlet
• Multinomial
• DirichletMultinomial - see https://github.com/pymc-devs/pymc/pull/5234