With the brush asset project, the `Paint` `brush` and `eraser_brush`
properties were effectively turned into a convenient cache of the active
brush. A related operator, `paint.brush_set` was also removed in favor
of `brush.asset_activate`
While this is technically a breaking change to the API, it currently
seems better to align this property with expected usage & other recent
changes rather than allow users to set a property that may not behave as
expected.
There are two currently known side effects that setting this property
via the Python API has that the equivalent call to brush.asset_activate
does not:
* Changing this property via the console or script, peforming a stroke
and then undoing the stroke causes the active brush to change - this
directly contrasts with the normal experience of using the asset
shelf where brush changes are not affected by undo
* The asset shelf itself does not update the currently active brush
until a subsequent mouseover
Pull Request: https://projects.blender.org/blender/blender/pulls/131991
9e8c037375