[Unreal] Adding indicator that shows you need to export static geometry

[JohnMega]

This PR adds an indicator that tells you that you need to export the static geometry. This indicator applies to the following actions within the editor:

1. Changing the Transform of actors that contain a SteamAudioGeometryComponent.
2. Deleting actors that contain a SteamAudioGeometryComponent.
3. Attaching the SteamAudioGeometryComponent to StaticMesh actors.

This indicator also supports the undo command.

Media

Video demonstrating the feature:

feature.mp4