Non-terrain-gem changes in support of upcoming terrain work. (#3345)

In preparation for a prototype Terrain Gem to get submitted, there are a few changes that are needed outside of the Terrain Gem as well:

The TerrainDataNotificationBus lives in AzFramework/Terrain, and needed to be extended to contain an optional OnTerrainDataChanged event to notify other systems when a terrain region has changed.
The HeightmapUpdateNotificationBus was removed, as this was a legacy file from the old already-removed terrain system.
The EditorWrappedComponentBase<> wrapper received a small optimization to ensure that ConfigurationChanged() is only called when the value of visibility actually changes. With prefabs, it appears that sometimes OnEntityVisibilityChanged could be called multiple times in a row with the same visibility value.
The TerrainSurfaceDataSystemComponent was updated to use the correct busses, and is ready to be moved to the Terrain Gem in a subsequent PR.

Signed-off-by: Mike Balfour 82224783+mbalfour-amzn@users.noreply.github.com

Gems/SurfaceData/Code/Source/SurfaceDataModule.cpp

@@ -20,7 +20,7 @@ namespace SurfaceData
             SurfaceDataSystemComponent::CreateDescriptor(),
             SurfaceDataColliderComponent::CreateDescriptor(),
             SurfaceDataShapeComponent::CreateDescriptor(),
-            TerrainSurfaceDataSystemComponent::CreateDescriptor(),
+            Terrain::TerrainSurfaceDataSystemComponent::CreateDescriptor(),
         });
     }
 
@@ -28,7 +28,7 @@ namespace SurfaceData
     {
         return AZ::ComponentTypeList{
             azrtti_typeid<SurfaceDataSystemComponent>(),
-            azrtti_typeid<TerrainSurfaceDataSystemComponent>(),
+            azrtti_typeid<Terrain::TerrainSurfaceDataSystemComponent>(),
         };
     }
 }