[FIX] spreadsheet: Use actual scss variables

The style was using hardcoded css values for its button. unfortunately,
since it was not based on global varialbes, the colors are now outdated.

Task 3047620

closes odoo/odoo#105889

X-original-commit: 777a831cd7e3096de9421c224e192ef7c718c77f
Signed-off-by: Pierre Rousseau (pro) <pro@odoo.com>

addons/spreadsheet/static/src/o_spreadsheet/o_spreadsheet_extended.scss

@@ -14,17 +14,17 @@
     color: #666;
 
     &.o_global_filter_save {
-        color: #008784;
-        border-color: #008784;
+        color: $o-brand-primary;
+        border-color: $o-brand-primary;
     }
 
     &.o_delete_element {
         color: #fff;
-        background-color: #dc3545;
-        border-color: #dc3545;
+        background-color: map-get($theme-colors, "danger");
+        border-color: map-get($theme-colors, "danger");
 
         &:hover:enabled {
-            background-color: #c82333;
+            background-color: darken(map-get($theme-colors, "danger"), 7%);
             border-color: #bd2130;
         }
     }