Feat/small fixes

[giuliana-gladeye]

This branch includes small fixes for a few of the items detected on feat/docs branch FUTURE_IMPROVEMENTS.md:

• Search Bar — the clear button uses name="XIcon". Lucide's canonical icon is X (XIcon is an alias that exists only in newer versions). If the installed lucide version lacks the alias, IconButton warns and renders null, so the clear button silently disappears. Prefer name="X". packages/ui/src/components/search-bar/search-bar.tsx
• Checkbox — stray trailing space / {' '} inside the indicator markup. Harmless, minor cleanup. packages/ui/src/components/checkbox/checkbox.tsx
• Icon — an unknown Lucide string name throws (Icon "" not found), crashing the render, whereas Icon Button with an unknown name only warns and returns null. Align the two: either both throw or both degrade gracefully. packages/ui/src/components/icon/icon.tsx · packages/ui/src/components/icon-button/icon-button.tsx

@Shrinks99 Only this few were done as the others would likely involve docs updates (which we need feat/docs PR approved first) or Gov Studio upgrades (which is more work there so waiting for actual go ahead on those)