Fixes (web): Optimized search page style and functionality #3221 (#9627)

### What problem does this PR solve?

Fixes (web): Optimized search page style and functionality #3221

- Updated search page and view title styles
- Modified dataset list and multi-select control styles
- Optimized text field and button styles
- Updated filter button icons
- Adjusted metadata filter styles
- Added default descriptions for the smart assistant

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/components/ui/textarea.tsx

@@ -54,7 +54,7 @@ const Textarea = forwardRef<HTMLTextAreaElement, TextareaProps>(
     return (
       <textarea
         className={cn(
-          'flex min-h-[80px] w-full bg-bg-card rounded-md border border-input px-3 py-2 text-base ring-offset-background placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 md:text-sm overflow-hidden',
+          'flex min-h-[80px] w-full bg-bg-input rounded-md border border-input px-3 py-2 text-base ring-offset-background placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 md:text-sm overflow-hidden',
           className,
         )}
         rows={autoSize?.minRows ?? props.rows ?? undefined}