Pages menu tree - moving lower level node to the top most node doesnt seem to fire move event

## To Reproduce

Step by step instructions to reproduce the behavior:

> 1. Open the pages menu (Reorganize Pages modal)
> 2. Move a lower node above the top most node
> 3. Click finished on modal
> 4. Page refreshes
> 5. Reopen pages menu, no change/save for ordering

## Expected behavior
> When you move a lower level node to the top most node it should save the wanted ordering

## Describe the bug
> It seems that the move event for the top node is not firing when moving a lower level node to the top position in the pages menu tree. The move event does fire if/when you adjust the menu nodes in the opposite fashion.

## Details

**Version of Node.js:**
v8.11.4

**Server Operating System:**
MacOS Mojave

**Screenshots**
Please find a link to a video of the issue I am experiencing with the pages tree movement node movement https://www.loom.com/share/7bca3e9d4a5b4512b7dcaa19b5f6847b

Start by reproducing the issue in the Reorganize Pages modal: move a lower-level node above the topmost node, finish, and reopen the menu. Trace the pages menu tree's move event handling and verify that the new ordering persists after refresh and reopening.

Written by the indexing model from the issue text.