fix: fix horizontal scrolling in navigator (#4813)

## Description

Navigator will get horizontal scrollbars when necessary.

## Steps for reproduction

1. click button
2. expect xyz

## Code Review

- [ ] hi @kof, I need you to do
  - conceptual review (architecture, feature-correctness)
  - detailed review (read every line)
  - test it on preview

## Before requesting a review

- [ ] made a self-review
- [ ] added inline comments where things may be not obvious (the "why",
not "what")

## Before merging

- [ ] tested locally and on preview environment (preview dev login:
0000)
- [ ] updated [test
cases](https://github.com/webstudio-is/webstudio/blob/main/apps/builder/docs/test-cases.md)
document
- [ ] added tests
- [ ] if any new env variables are added, added them to `.env` file

Author: kof

packages/design-system/src/components/scroll-area.tsx

@@ -26,12 +26,11 @@ const ScrollAreaScrollbar = styled(Scrollbar, {
   touchAction: "none",
   '&[data-orientation="vertical"]': {
     width: theme.spacing[6],
-    paddingRight: 3,
   },
   '&[data-orientation="horizontal"]': {
     flexDirection: "column",
     height: theme.spacing[6],
-    paddingBottom: 3,
+    "--radix-scroll-area-thumb-height": theme.spacing[4],
   },
 
   variants: {