feat: command group distinction (#854)

fixes #836 

- Explicit `div` is used instead of `<CommandSeparator/>` , since it
failed to render borders for dynamic search results, but only works for
initial menu.

(initial menu)

![cgrp](https://github.com/documenso/documenso/assets/85569489/0ee0aabb-c780-4c03-97e7-cf9905bb9b61)

(search results)

![dyanmic](https://github.com/documenso/documenso/assets/85569489/74b0a714-a952-4516-9787-53d50a60b78c)

apps/web/src/components/(dashboard)/common/command-menu.tsx

@@ -252,7 +252,11 @@ const ThemeCommands = ({ setTheme }: { setTheme: (_theme: string) => void }) =>
   );
 
   return THEMES.map((theme) => (
-    <CommandItem key={theme.theme} onSelect={() => setTheme(theme.theme)}>
+    <CommandItem
+      key={theme.theme}
+      onSelect={() => setTheme(theme.theme)}
+      className="mx-2 first:mt-2 last:mb-2"
+    >
       <theme.icon className="mr-2" />
       {theme.label}
     </CommandItem>