Forms: delete left border from select arrow for now

app/styles/forms.scss

@@ -482,7 +482,6 @@ code {
       content: "";
       position: absolute;
       right: 12px;
-      border-left: 1px solid var(--highlight-text-color);
       height: calc(100% - 8px);
       padding-left: 12px;
       pointer-events: none;