XP2B 4.4.0 breakage in Blender >5.0.0 #758

XP2B does not work in Blender 5.0.0 and newer because of a change in actions handling. Imports and exports fail with:

Python: Traceback (most recent call last):
File "/home/.../.config/blender/5.0/scripts/addons/io_xplane2blender/xplane_ops.py", line 586, in execute
bpy.ops.export.xplane_obj(filepath=self.initial_dir, export_is_relative=True)
File "/media/X-Plane/X-Plane_Utilities/blender-5.0.0-linux-x64/5.0/scripts/modules/bpy/ops.py", line 109, in call
ret = _op_call(self.idname_py(), kw)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: Error: Python: Traceback (most recent call last):
File "/home/.../.config/blender/5.0/scripts/addons/io_xplane2blender/xplane_types/xplane_file.py", line 75, in >createFilesFromBlenderRootObjects
xplane_file = createFileFromBlenderRootObject(potential_root, view_layer)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/.../.config/blender/5.0/scripts/addons/io_xplane2blender/xplane_types/xplane_file.py", line 131, in >createFileFromBlenderRootObject
xplane_file = XPlaneFile(filename, layer_props)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/.../.config/blender/5.0/scripts/addons/io_xplane2blender/xplane_types/xplane_file.py", line 252, in init
_pre_scan_all_keyframes()
File "/home/.../.config/blender/5.0/scripts/addons/io_xplane2blender/xplane_types/xplane_file.py", line 181, in _pre_scan_all_keyframes
{
File "/home/.../.config/blender/5.0/scripts/addons/io_xplane2blender/xplane_types/xplane_file.py", line 184, in
for fcurve in action.fcurves
^^^^^^^^^^^^^^
AttributeError: 'Action' object has no attribute 'fcurves'
Location: ..../blender-5.0.0-linux-x64/5.0/scripts/modules/bpy/ops.py:109

This is due to removal of non-slotted actions support in Blender 5.0.0.

See: https://developer.blender.org/docs/release_notes/5.0/python_api/ and https://developer.blender.org/docs/release_notes/4.4/upgrading/slotted_actions/