chore: Fix 25795 (#26823)

Co-authored-by: crazywoola <100913391+crazywoola@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

web/app/components/base/chat/embedded-chatbot/header/index.tsx

@@ -135,7 +135,7 @@ const Header: FC<IHeaderProps> = ({
   return (
     <div
       className={cn('flex h-14 shrink-0 items-center justify-between rounded-t-2xl px-3')}
-      style={Object.assign({}, CssTransform(theme?.backgroundHeaderColorStyle ?? ''), CssTransform(theme?.headerBorderBottomStyle ?? ''))}
+      style={CssTransform(theme?.headerBorderBottomStyle ?? '')}
     >
       <div className="flex grow items-center space-x-3">
         {customerIcon}