Downgrade @canonical/global-nav version (#5433)

Downgrade @canonical/global-nav from version 3.8.0 to 3.7.3.

Author: alvaromateo

package.json

@@ -26,7 +26,7 @@
     "@babel/preset-react": "7.26.3",
     "@babel/preset-typescript": "7.26.0",
     "@canonical/cookie-policy": "3.6.5",
-    "@canonical/global-nav": "3.8.0",
+    "@canonical/global-nav": "3.7.3",
     "@canonical/react-components": "3.6.0",
     "@canonical/store-components": "0.54.2",
     "@dnd-kit/core": "6.3.1",