Improve styling of Data tab for Line/Area/Bar charts (#11250)

* make add series/breakout buttons nicer

* spacing

frontend/src/metabase/visualizations/components/settings/ChartSettingFieldPicker.jsx

@@ -56,8 +56,6 @@ const ChartSettingFieldPicker = ({
         className={cx("ml1 text-medium text-brand-hover cursor-pointer", {
           "disabled hidden": !onRemove,
         })}
-        width={12}
-        height={12}
         onClick={onRemove}
       />
     </div>

frontend/src/metabase/visualizations/components/settings/ChartSettingFieldsPicker.jsx

@@ -45,8 +45,9 @@ const ChartSettingFieldsPicker = ({
       <span className="text-error">{t`error`}</span>
     )}
     {addAnother && (
-      <div className="mt1">
+      <div className="mt2 mb3">
         <a
+          className="text-brand text-bold py1 px2 rounded bg-light bg-medium-hover"
           onClick={() => {
             const remaining = options.filter(o => value.indexOf(o.value) < 0);
             if (remaining.length === 1) {