[FIX] theme_odoo_experts: fix "references" snippet paddings

The snippet was switched to grid mode in this theme but the padding
classes on columns were not removed.

Related to task-4373543

Part-of: odoo/design-themes#1054
Related: odoo/odoo#189299
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

test_themes/tests/test_new_page_templates.py

@@ -155,6 +155,7 @@ class TestNewPageTemplates(TransactionCase):
         self.assertGreater(len(view_ids), 1250, "Test should have encountered a lot of views")
         self.assertFalse(errors, "No error should have been collected")
 
+    # TODO should handle the fact that grid items can't have padding classes
     def test_render_applied_templates(self):
         View = self.env['ir.ui.view']
         errors = []