[REM] theme_*: remove useless scss variable overrides

This commit removes the overrides of scss variables that are set to the
default value and duplicated overrides.

task-2463604

closes odoo/design-themes#768

Signed-off-by: Outagant Mehdi (mou) <mou@odoo.com>

theme_artists/static/src/scss/primary_variables.scss

@@ -99,7 +99,6 @@ $o-website-values-palettes: (
         'headings-font': 'Oxygen',
         'btn-ripple': true,
         'header-template': 'hamburger',
-        'hamburger-position': 'left',
         'footer-template': 'centered',
         'link-underline': 'never',
     ),