[CSS] Removed unnecessary box-shadow rules that slowed down performance (see edit feeds page)

public/assets/default_theme/css/pages/settings.css

@@ -13,7 +13,7 @@
 }
 
 .section-title-settings[open] {
-    border-left: 2px solid var(--accent);
+    border-left: 2px solid var(--foreground);
 }
 
 .section-title-settings[open] > summary:first-child {

public/assets/default_theme/css/widgets/buttons.css

@@ -136,7 +136,6 @@ textarea {
     padding: 6px 8px !important;
     border-radius: var(--smaller);
     border: 2px solid var(--border) !important;
-    box-shadow: var(--shadow) !important;
     width: inherit;
     max-width: border-box !important;
 }