feat: Add support for dark mode in dashboard (#7460)

- Add config for TailwindCSS
- Enable HMR
- Add a config in LocalStorage for Dark Mode

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/javascript/dashboard/assets/scss/widgets/_forms.scss

@@ -61,3 +61,7 @@ input {
     border-color: var(--r-400);
   }
 }
+
+label {
+  @apply dark:text-slate-300;
+}