chore: update the xmas asset to new year asset (#11119)

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<!-- start pr-codex -->

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## PR-Codex overview
This PR updates the styling for the `XmasEffect` component, changing its
dimensions and background image to reflect a new year's theme instead of
a Christmas theme.

### Detailed summary
- Changed `width` from `16vw` to `26vw`
- Changed `height` from `19.2vw` to `15vw`
- Updated `background` image URL from a Christmas tree to a new year's
theme image

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question}`

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Author: Chef-Yogi

apps/web/src/views/SwapSimplify/V4Swap/XmasEffect.tsx

@@ -33,9 +33,9 @@ const XmaxTree = styled.div`
   }
 
   left: 1%;
-  width: 16vw;
-  height: 19.2vw;
-  background: url('${ASSET_CDN}/web/swap/xmas/xmas-tree-${({ theme }) => (theme.isDark ? 'dark' : 'light')}.png')
+  width: 26vw;
+  height: 15vw;
+  background: url('${ASSET_CDN}/web/swap/new-year/new-year-${({ theme }) => (theme.isDark ? 'dark' : 'light')}.png')
     no-repeat center center fixed;
   background-size: cover;
 `