AssetDB: Custom File List only filters assets, not asset usages

[henbagle]

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The more information you provide, the easier it will be for us to reproduce the issue.

Describe the bug
When using the custom file list feature in Asset Database, each tab will only show you assets that are in those chosen files. However, selecting any of those assets on the left hand panel will show ALL usages of those assets across the entire game in the right hand panel.

Only one file is in the filtered file list, showing a very small number of meshes. However, many many usages show up in the right hand panel.

Is this how we want AssetDB to work? It makes sense to me that if you are filtering to look in a specific subset in files, that you would only want to see the usages in those files. EG. You want to find all the BioPawns in a certain level section, so you add those files to the filelist and select BioPawn in the Classes tab.

To Reproduce
Add a single file to the filtered file list.
Enable the filter for the list in the Filter menu.
Select any asset.

Other information
Was this how AssetDB worked before the rewrite that added the material bool filters? The entire filter system was rewritten from the ground up for that update.

Some feedback would be great on whether this is a desired feature, or if it's fine as it is.