Prim highlighted in Outliner after clearing UFE selection on `SelectionReplaced` notification

Hi all,

We're encountering an issue with selection highlighting in the Outliner when we clear the UFE selection inside a `ufe.SelectionReplaced` notification. The Outliner is still highlighting the selected prim despite nothing is actually selected. Note that we only see this issue when selecting a prim in the Outliner. When selecting a prim in the view port the selection is cleared as expected and nothing is highlighted in the Outliner.

**Steps to reproduce**
1. Create a stage with a new layer & add a prim in the Outliner (context menu > `Add New Prim`).
2. Add `MySelectionObserver` to the global selection:
```python
import ufe

class MySelectionObserver(ufe.Observer):
def __call__(self, notification):
if isinstance(notification, ufe.SelectionReplaced):
self._clearSelection(notification)

def _clearSelection(notification):
selection = ufe.GlobalSelection.get()
selection.clear()

observer = MySelectionObserver()
selection = ufe.GlobalSelection.get()
selection.addObserver(observer)
```
3. Select the previously created prim in the Outliner. Note that Outliner is still highlighting the selection. However, the prim's parents are not indicating the selection as it would be expected usually.
4. Query the global selection and notice that nothing is selected even though the Outliner is highlighting the selected prim.
```python
>>> print(item.path() for item in ufe.GlobalSelection.get())
[]
```

**Specs (if applicable):**
- CentOS Linux 7.4.1708
- Maya 2023.0.0-4.0
- MayaUSD Plugin 0.18.0