BUG: B matrix orientation in SEM workflow notebook is incorrect.

[NathanielF]

SEM Workflow:
https://www.pymc.io/projects/examples/en/latest/case_studies/bayesian_sem_workflow.html:

Issue description

There is a minor issue in the interpretation of the B matrix specification. The orientation of the target -> predictors encoding is incorrect. The correct structure is inverted. The row indexes denote the target the column indexes the predictors

Proposed solution

Will add a fix to correct the orientation. The interpretation i this case doesn't change, it's how the mistake snuck through.