This uses the changes from ef68a37e5d to create IDProperties
for exposed boolean sockets with a boolean type instead of an integer
with a [0,1] range. Existing properties and values are converted
automatically.
For forward compatibility, the properties are switched to the integer
type for saving. Otherwise older versions crash immediately when opening
a newer file. The "Use Attribute" IDProperties aren't changed here,
since that wouldn't have a visible benefit.
Differential Revision: https://developer.blender.org/D12816