[BUG] Interaction Mode Manager component doesn't show CanvasProxyInteractor type in menu

[anonymous2585]

Describe the bug

In the Interaction Mode Manager component, the Prioritized Interaction Modes list doesn't allow user to select the CanvasProxyInteractor type, while it's used in samples scene and MRTK Rig prefab.

To reproduce

Steps to reproduce the behavior:

1. Open scene HandInteractionExample
2. In hierarchy, select GameObject MRTK Interaction Manager
3. In inspector, on the component Interaction Mode Manager, unfold the Prioritized Interaction Modes
4. Unfold the FlatScreen mode
5. Change the value from CanvasProxyInteractor to another type
6. Try to set back the value to CanvasProxyInteractor, the option is not on the list

Expected behavior

The contextual menu shows the namespace MixedReality.Toolkit.UXCore and user can choose the CanvasProxyInteractor type.

Screenshot

Your setup

• Unity Version 2021.3.21f1
• MRTK Commit main@d818d18