badge: trim the height-fix comment

mara: 'thinking badge size is bigger for some reason'. Several badges
fold a leading glyph straight into their value text (STATE_LABELS'
emoji in Root.tsx, the pause/resume glyphs) rather than using Badge's
dedicated icon prop, and an emoji's (or its tofu fallback's) own
line-box commonly exceeds the surrounding text's line-height: 1.4 in
most fonts, inflating just that badge's height against its siblings.

Fix: line-height: 1 on .ui-badge-value forces every badge back to the
same box regardless of which glyph a given state happens to carry.
Verified with a real headless-chromium repro of the exact thinking/
pause height mismatch from her screenshot, before and after.

frontend/packages/shared/src/badge/Badge.css

@@ -90,6 +90,8 @@
 }
 .ui-badge-value {
   color: var(--fg);
+  /* Fixes badge with emoji having different size. */
+  line-height: 1;
 }
 .ui-badge-caret {
   font-size: 0.75em;