The PRCurve Visualizer has an issue in the .fit() method for multi-class classifier models

[pdamodaran]

Describe the bug In the PRCurve Visualizer, the multi-class classifier models get wrapped up in a OneVsRestClassifier but this classifier gets ignored in the call to super and does not get fitted as a result. This results in an error in rendering the visualizer as the num_class parameter is not set

To Reproduce

This was discovered through Issue #1190.