Fix: Dashboard history diff & white theme fix (#16231)

public/sass/pages/_history.scss

@@ -188,7 +188,7 @@
 
 .diff-change-group {
   width: 100%;
-  color: rgba(223, 224, 225, 0.6);
+  color: $text-color;
   margin-bottom: 14px;
 }