Possible bug with GAOGlobalDistanceFieldCacheMostlyStaticSeparately

The Global Distance Field can constantly update, even when the camera is stationary, in large World Partition maps. This bug requires a large amount of the World Partition map to be loaded to reproduce.

If the reproduction steps do not work, try adding a landscape.

1. Download City Sample test project
2. Add the following changes to the DefaultEngine.ini:
```
[/Script/Engine.RendererSettings]
…
; DistanceFields weren't supported by default in the project, so had to toggle this on
r.DistanceFields.SupportEvenIfHardwareRayTracingSupported=1

; Half resolution Distance Fields
r.LumenScene.GlobalSDF.Resolution=124
r.DistanceFields.BrickAtlasSizeXYInBricks=64
r.DistanceFields.BrickAtlasMaxSizeZ=16

[SystemSettings]
…
; r.DistanceFields.SupportEvenIfHardwareRayTracingSupported=0 COMMENT THIS LINE OUT
```
2. Open the project, and open the map "/Game/Maps/Big_City_LVL" or "/Game/Maps/Small_City_LVL"
4. Load a large section of the map, about 1/3 of the island for Big City, or the whole island for Small City.
5. Under Show->Visualize, enable Global Distance Field visualization
6. Verify Global Distance Field is working. If it is not, fix your DefaultEngine.ini
7. Execute the console commands :

• "r.GlobalDistanceField.Debug.ShowStats 1"
• "r.AOGlobalDistanceFieldCacheMostlyStaticSeparately 1"
• "stat gpu"

8. Observe that the "Updated" field in the debug text is displaying a large number when the camera is still
9. Take note of the stat field "Global Distance Field Update" to compare with later
10. Execute the console command "r.AOGlobalDistanceFieldCacheMostlyStaticSeparately 0"
11. Observe that the "Updated" field in the debug text remains 0 when the camera is still
12: Observe that the current value of the stat field "Global Distance Field Update" is much less than the previous value noted in step 10.