fixup! [ozone/wayland] Guard against spurious wl_pointer.enter|leave events

This CL partially steps back on the approach taken in [1], where
it was decided to suppress pointer enter|leave events during both
window and data drag.

It turns out that WaylandDataDragController sets its state to
|started| before even sending the StartDrag() request to the compositor.
So the compositor has no way to send the (expected) pointer leave
event without triggering the warning. This was observed by
<max@igalia.com>, while reworking on ui-controls protocol, and observing
some mishave.

[1] https://crrev.com/c/4123067

BUG=1340214
R=max@igalia.com, nickdiego@igalia.com

Change-Id: Ie5cb1715de887b78798b4ac732e216f911dd6a1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4177994
Reviewed-by: Nick Yamane <nickdiego@igalia.com>
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/main@{#1094219}