[FIX] web_editor: fix gap between transformed shape and next section

Previously, when flipping some shapes vertically on chrome, and
vertically or horizontally on firefox, there was a gap of 1px or less at
some screen widths. This is caused by the way these browsers render
backgrounds on transformed elements. It seems like firefox will round
the size of the element to render the background image on it if the
element is transformed, while chrome will always render the background
at the correct size (or render it at a larger size and clip it to the
correct size after the fact), but will round the coordinates of the
symmetry point, causing only the vertical flip to have this issue, and
only if the background image would not extend beyond the bounds of the
element (on firefox, even shapes that would extend beyond the bounds of
the element would showcase a gap, eg origins 1)

This commit fixes that by applying the transform to the SVG rather than
to the element, by use of the shapes controller.

task-2369560

closes odoo/odoo#61114

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