feat(theme): use IBM Plex Mono for code and numerical displays (#37366)

Co-authored-by: Mehmet Salih Yavuz <salih.yavuz@proton.me>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

superset-frontend/src/SqlLab/components/ResultSet/index.tsx

@@ -531,6 +531,7 @@ const ResultSet = ({
           placement="left"
         >
           <Label
+            monospace
             css={css`
               line-height: ${theme.fontSizeLG}px;
             `}