Fix batch of unreleased dark-mode and UI bugs (#44978)

\

frontend/components/forms/fields/Dropdown/_styles.scss

@@ -94,31 +94,17 @@
     .Select-value-icon {
       border: 0;
       float: right;
-      position: relative;
       line-height: 28px;
       width: 20px;
       padding: 0;
       margin: 0 5px;
-      text-indent: -999em;
-
-      &::after {
-        transition: color 150ms ease-in-out;
-        content: url(../assets/images/icon-close-fleet-black-16x16@2x.png);
-        transform: scale(0.5);
-        position: absolute;
-        top: -5px;
-        left: -5px;
-        visibility: visible;
-        font-size: $x-small;
-        color: $ui-gray;
-        text-indent: 0;
-      }
+      text-align: center;
+      font-size: $small;
+      color: $ui-fleet-black-50;
+      transition: color 150ms ease-in-out;
 
       &:hover {
-        &::after {
-          content: url("../assets/images/icon-close-fleet-black-16x16@2x.png");
-          transform: scale(0.5);
-        }
+        color: $core-fleet-black;
       }
     }
 
@@ -296,6 +282,15 @@
     line-height: 34px;
     box-sizing: border-box;
   }
+
+  .Select-clear-zone {
+    color: $ui-fleet-black-50;
+    transition: color 150ms ease-in-out;
+
+    &:hover {
+      color: $core-fleet-black;
+    }
+  }
   .Select-input {
     color: $core-fleet-black;
     font-size: $x-small;