Issue:

> Set bg color combination for a snippet... > Save
> Edit mode > Select the snippet
> Open color palette in bg option
> Hover a color option
> When a color button is left, the preview is cancelled
  but the color combination class is not applied anymore.

In '_computeWidgetState' (for 'selectStyle' method), the right
value ('o_cci') is not returned because we get empty "colorNames"
(the "colorPalette" is not rendered on start).

The goal of this commit is to fix this behaviour by rendering the
colorPalette in start for snippet options, this way, the new code
won't affect the speed fix added in [1] for 'OPTIONS' tab.

[1]: https://github.com/odoo/odoo/pull/65223/commits/ce54c3f21293513673cb1fc6073ada5f0a2b5641



task-2538326

closes odoo/odoo#71174

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