Point Lights Invlidate Virtual Shadow Map Cache when at a distance from attenuation radius

When the camera is outside of a certain distance from a point lights attenuation radius the VSM of that point light stops caching shadow maps.

This can also be reflected in the output from the 'r.Shadow.Virtual.Stats 1' console command

1. Create a project and a basic level
2. Add a point light to the level
3. Move the point light to intersect with the Floor static mesh
4. Enable 'Virtual Shadow Map -> Cached Page' view mode
5. Select the Point Light in the World Outliner
6. Move the camera to look at the point light and adjust the camera distance to 'zoom out' away from the point light
7. Observe the cache indicator of the point light changing from green to red.

Expected behavior - the virtual shadow map cache would not be invalidated as the camera moves away from the point light.