fix change detection in hierarchy ui

[aarthificial]

Fixes a bug where hierarchy_ui doesn't return true when the selection is modified by clicking on a nested entity.
This problem can be reproduced by running the egui_dock exmaple:

cargo run --example egui_dock

1. Expand the Pbr Mesh (6v0) entity on the left
2. Select any resource in Resources
3. Click on the nested PointLight (7v0) on the left

Doing so should update the inspector to display information about the point light but it doesn't because hierarchy_ui doesn't return true in this case:

bevy-inspector-egui/crates/bevy-inspector-egui/examples/integrations/egui_dock.rs

Lines 213 to 216 in 1b916a0

	let selected = hierarchy_ui(self.world, ui, self.selected_entities);
	if selected {
	*self.selection = InspectorSelection::Entities;
	}

[jakobhellermann]

Thanks!