style: SIP-34 labels (#10403)

* style: SIP-34 labels

Aligning with SIP-34 designs for labels/pills. Going uppercase fixes the
padding issues we had before, and the rounder pills look better.

Cleaning up some CSS in the process

* lint

superset-frontend/src/explore/components/RowCountLabel.jsx

@@ -47,10 +47,7 @@ export default function RowCountLabel({ rowcount, limit, suffix }) {
   );
   return (
     <TooltipWrapper label="tt-rowcount" tooltip={tooltip}>
-      <Label
-        bsStyle={bsStyle}
-        style={{ fontSize: '10px', marginRight: '5px', cursor: 'pointer' }}
-      >
+      <Label bsStyle={bsStyle} className="m-r-5 pointer">
         {formattedRowCount} {suffix}
       </Label>
     </TooltipWrapper>