The bone collection operator was not updated to handle the new flag
which is now on the `bPoseChannel` instead of the `Bone`.
For this to work, the operator now needs the `bArmature` as well as the `Object`
and they need to be in sync. Additional code was added to the poll function
to ensure this is the case.
As a bonus, when working with multiple armatures this now works as expected
where only the bones of the active armature are selected even if the armature is
shared. The active object is determined by the last bone clicked.
Pull Request: https://projects.blender.org/blender/blender/pulls/148185
f4fd52796f