Previously, the number of action map subactions was limited to two per
action (identified by user_path0, user_path1), however for devices with
more than two user paths (e.g. Vive Tracker) it will be useful to
support a variable amount instead.
For example, a single pose action could then be used to query the
positions of all connected trackers, with each tracker having its own
subaction tracking space.
NOTE: This introduces breaking changes for the XR Python API as follows:
- XrActionMapItem: The new `user_paths` collection property
replaces the `user_path0`/`user_path1` properties.
- XrActionMapBinding: The new `component_paths` collection property
replaces the `component_path0`/`component_path1` properties.
Reviewed By: Severin
Differential Revision: https://developer.blender.org/D13949
6a8709ba13