[FIX] web_editor: do not call onBlur/onFocus on active snippet click

Before this commit, when clicking inside a snippet which is already
enabled, it was disabled then re-enabled... which had the side effect
of calling onBlur/onFocus methods. This can be a problem with some
onFocus/onBlur implementation relying on the old behavior.

Note: this commit restores the exact same behavior as before. If an
internal snippet of the active one is clicked, then we still call the
onBlur then onFocus for the old active one (the parent) as the actual
enabled snippet changed (even if it is simply a child snippet).

closes odoo/odoo#39250

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>