[FIX] web_editor: toolbar glitch when selecting media

The code snippet removed by this commit had no useful effect, as
`selection.addRange(range)` a few line above triggers
`OdooEditor._onSelectionChange`, which repositions the toolbar
elsewhere.

The result was a "glitch": the toolbar would briefly be displayed over
the top left corner of the media before finally being displayed above
(or below) it.

This commit removes such undesirable effect.

task-3347942

closes odoo/odoo#123568

Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>