[Maint] Update test fixtures to not use Boston

[eddiebergman]

API Change Deprecates datasets.load_boston in 1.0 and it will be removed in 1.2. Alternative code snippets to load similar datasets are provided. Please report to the docstring of the function for details. scikit-learn/scikit-learn#20729 by Guillaume Lemaitre.

As seen in #1611

We use load_boston for a lot of our individual component testing so this will have to be updated to some other datasets. This will come into effect with scikit learn 1.2

[AmirAlavi]

@eddiebergman would the diabetes dataset be a suitable replacement?

Here are the stats of the diabetes dataset:

Samples total	442
Dimensionality	10
Features	real, -.2 < x < .2
Targets	integer 25 - 346

In comparison to the prior Boston home prices dataset:

Samples total	506
Dimensionality	13
Features	real, positive
Targets	real 5. - 50.