Shallow Select mode fails to transfer selection to selected sibling

[Keavon]

In the Select tool with Shallow Select mode set, I should be able to single-click the green shape in the viewport and transfer the selection to it, because it is the sibling of the already-selected layer. Currently it incorrectly selects the shared parent folder instead of the green shape's "Boolean Operation" layer if it's clicked. Clicking a layer within the same shared ancestor shouldn't return selection to being outside the scope of that shared ancestor.

[mTvare6]

Fixed in #2604