Item overview fail to load upstream extracts from physical bioassays

[Nicklas Nordborg]

This normally works but if:

• The overview is started at or passes a derived bioassay which has an associated extract, and...
• The associated extract is not found as an immediate parent or grand-parent of the flow cell

Then, the item overview stops at the flow cell level. Expected behavior is to load the paths of parent extract that lead to the associated extract.

See also #1806

[Nicklas Nordborg]

(In [6455]) Fixes #1805: Item overview fail to load upstream extracts from physical bioassays