Moves undefined fallback from client to server side for cursor parameter
Ensures consistent pagination behavior when fetching links from KV storage
This prevents potential edge cases where undefined cursor values could be handled differently between client and server.
Replaces the cursor value in the API request with `undefined` if it is falsy. This prevents potential issues with null values being sent in the query, ensuring a more reliable API interaction.
Improves overall stability when fetching link data from the server.
