Multiple errors are thrown when the added component is removed from prefab override content panel.
Steps to repro:
1. Create a new project.
2. Hierarchy > Create Cube.
3. Select Cube > Drag in Project > Asset to make prefab
4. Hierarchy > Cube > Inspector > Add Component > Add any component Ex: Audio Source, Rigidbody
5. Overrides > added component
6. Click on revert on diff. panel.

Actual Result:
Reverting the added component from prefab override content panel throws multiple errors.

Expected Result:
Reverting changes in should close panel without throwing an exception

Reproducible in:
2019.3.0a12, 2019.3.0a3.

Working Fine in:
2019.3.0a2, 2019.2.1f1.

Environment:
Windows and Mac

StackTrace:
1. MissingReferenceException: The object of type 'Rigidbody' has been destroyed but you are still trying to access it.

2. SerializedObject target has been destroyed.
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

3. GUI Error: You are pushing more GUIClips than you are popping. Make sure they are balanced.
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)