fix(ui): Fix Sidebar not having a background color (#11347)

Author: andreiborza

src/components/sidebar/style.module.scss

@@ -7,6 +7,7 @@
 .sidebar {
   --sidebar-item-bg-hover: var(--accent-purple-light);
   --sidebar-item-color: var(--accent-purple);
+  background-color: var(--color-page-background);
   top: var(--header-height);
   bottom: 0;
   flex-direction: column;