fix: remove empty :global selector that breaks Lightning CSS

Moved the sr-only comment from above the selector to inside it to prevent
Sass from generating an empty `:global {}` block in the CSS modules output.
This fixes build failures when using Rolldown Vite with Lightning CSS
minification, which throws "SyntaxError: Invalid empty selector".

Fixes #5989

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: martijnrusschen

src/stylesheets/datepicker.scss

@@ -2,8 +2,8 @@
 @use "variables" as *;
 @use "mixins" as *;
 
-/* sr-only utility class for accessibility */
 .react-datepicker__sr-only {
+  // sr-only utility class for accessibility
   position: absolute;
   width: 1px;
   height: 1px;