Fix CSS hover style for links styled as buttons

ui/static/css/common.css

@@ -459,10 +459,13 @@ a.button {
     color: var(--button-primary-color);
 }
 
+a.button-primary:hover,
+a.button-primary:focus,
 .button-primary:hover,
 .button-primary:focus {
     border-color: var(--button-primary-focus-border-color);
     background: var(--button-primary-focus-background);
+    color: var(--button-primary-color);
 }
 
 .button-danger {