*Steps to reproduce:*
# Create game object with a behavior graph agent in the scene and assign a behavior graph to it
# Make a prefab out of the game object
# Click on the behavior graph asset and press the "Delete Runtime Assets" button
# Open the graph and close the window to regenerate the runtime assets
# Click on the game object in the scene and observe the inspector (it gets updated with the new runtime graph)
# Click on the prefab and observe the inspector

*Actual results:* The prefab shows a missing reference for the graph

*Expected results:* The prefab references the runtime graph

*Reproducible with versions:* 
1.0.8

*Tested on (OS):* MacOS

*Notes:*
* Reversing steps 5 and 6, i.e. pressing the prefab first, makes it so that the prefab references the graph correctly