[SPEC] The scroll_id is no longer a required qs param

Can be passed in the body instead

rest-api-spec/api/clear_scroll.json

@@ -8,7 +8,6 @@
       "parts": {
         "scroll_id": {
           "type" : "list",
-          "required" : "true",
           "description" : "A comma-separated list of scroll IDs to clear"
         }
       },