FlaxEngine

Fix missing include files in packaged build

Fix tooltip for content items in Tree View mode

Merge branch 'envision3d-bugfix/tree-view-folder-deletion'

Merge branch 'bugfix/tree-view-folder-deletion' of https://github.com/envision3d/FlaxEngine into envision3d-bugfix/tree-view-folder-deletion

Fix skinned model retarget source asset filter to work after `AssetPicker` refactor with new validator