Asset selection can take a long time

[ItsPepperpot]

Sometimes selecting an asset in levels with many assets can take a long time (several seconds) before it appears selected with the gizmo + selection tint, especially in scenes with many objects.

To Reproduce

1. Open a level with many objects (e.g. BB02.HIP/HOP)
2. Click on an object to select it
3. Observe it takes a long time to be selected

[ItsPepperpot]

ArchiveEditor.SetSelectedIndices is causing asset selection to take a long time.
When you click in the 3D view, it will also change the selected layer on the layer combo box in the Archive Editor window.

This triggers the ArchiveEditor.comboBoxLayers_SelectedIndexChanged event - presumably causing every item in the Archive Editor asset list to be updated?

This takes about 800ms with BB02.hip and BB02.hop when selecting a Simple Object.

[ItsPepperpot]

It seems a large proportion of the time is spent here:

IndustrialPark/IndustrialPark/ArchiveEditor/ArchiveEditor.cs

Line 570 in ec5bb8b

listViewAssets.Items.AddRange(items.ToArray());

adding the items to listViewAssets takes a long time.