fix: update readwise example to work without duplicating nodes

this is a workaround to the fact that readwise use cursor pagination
instead of offset pagination, proper handling will be added later

examples/mock_data/Readwise/collection.bru

@@ -0,0 +1,9 @@
+auth {
+  mode: apikey
+}
+
+auth:apikey {
+  key: Authorization
+  value: Token {{API_KEY}}
+  placement: header
+}