Don't remove selection when hovering over a non-selectable DOM element (ianstormtaylor#4577)

* Don't remove selection when hovering over a non-selectable node

Fixes ianstormtaylor#4545

To reproduce the buggy behavior:

1. Create a page that renders a Slate element with a `contentEditable: false` element in it.
2. Start selecting some text with the mouse.
3. During the drag, mouseover the `contentEditable: false` element.

Expected behavior: After doing a drag-to-select with the mouse, from a valid anchor point on mousedown to a valid focus point on mouseup, the selection is set to those anchor and focus points.

Actual behavior: your selection is removed as soon as your mouse hits the `contentEditable: false` element. This is because the current behavior clears the selection if it is momentarily not a valid Slate location.

* Add changeset

Author: jameshfisher

.changeset/curly-timers-watch.md

@@ -0,0 +1,5 @@
+---
+'slate-react': patch
+---
+
+Fixed a bug that removed the selection when hovering over a non-selectable DOM element

packages/slate-react/src/components/editable.tsx

@@ -505,8 +505,6 @@ export const Editable = (props: EditableProps) => {
             exactMatch: false,
           })
           Transforms.select(editor, range)
-        } else {
-          Transforms.deselect(editor)
         }
       }
     }, 100),