Fix: Add e.preventDefault() to prevent page reload (shadcn-ui#2278)

Fixes shadcn-ui#2277

Add `e.preventDefault()` to prevent page reload in mail component

![image](https://github.com/shadcn-ui/ui/assets/106688422/d1373e8f-0c46-4f2e-8caf-2fcd2076b2fb)

apps/www/app/examples/mail/components/mail-display.tsx

@@ -236,7 +236,11 @@ export function MailDisplay({ mail }: MailDisplayProps) {
                     <Switch id="mute" aria-label="Mute thread" /> Mute this
                     thread
                   </Label>
-                  <Button size="sm" className="ml-auto">
+                  <Button
+                    onClick={(e) => e.preventDefault()}
+                    size="sm"
+                    className="ml-auto"
+                  >
                     Send
                   </Button>
                 </div>