Remove default linear gradient (#32277)

Remove the default invisible gradient causing the performance issue in #32266

. By removing the custom property, the linear gradient will become invalid, thus not appear by default.

There can still be a performance issue with striped tables though.

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

scss/_tables.scss

@@ -4,7 +4,6 @@
 
 .table {
   --#{$variable-prefix}table-bg: #{$table-bg};
-  --#{$variable-prefix}table-accent-bg: transparent;
   --#{$variable-prefix}table-striped-color: #{$table-striped-color};
   --#{$variable-prefix}table-striped-bg: #{$table-striped-bg};
   --#{$variable-prefix}table-active-color: #{$table-active-color};