data store: avoid possible race condition with reloaded deltas

* The cylc-ui typically opens two subscriptions:
  * One for all workflows (powers the workflows list down the left)
  * One for the workflow you have open (powers the Cylc views)
* This is for performance reasons as when the user switches workflow we
  only cancel latter subscription which avoids reloading all workflows.
* Because the reloaded delta would come through on both subscriptions
  there's the risk we could wipe the workflow's children, then
  re-populate them, only to wipe them again when the former subscription
  returned the reloaded delta.

src/graphql/queries.js

@@ -28,19 +28,6 @@ const WORKFLOW_DATA_FRAGMENT = `
 fragment WorkflowData on Workflow {
   id
   reloaded
-  status
-  statusMsg
-  owner
-  host
-  port
-  stateTotals
-  latestStateTasks(states: [
-    "failed",
-    "preparing",
-    "submit-failed",
-    "submitted",
-    "running"
-  ])
 }
 `
 
@@ -152,7 +139,22 @@ fragment UpdatedDelta on Updated {
   }
 }
 
-${WORKFLOW_DATA_FRAGMENT}
+fragment WorkflowData on Workflow {
+  id
+  status
+  statusMsg
+  owner
+  host
+  port
+  stateTotals
+  latestStateTasks(states: [
+    "failed",
+    "preparing",
+    "submit-failed",
+    "submitted",
+    "running"
+  ])
+}
 `
 
 /**