Fix cache update for schedules and policies

Changelog: fixed
EE: true

ee/app/assets/javascripts/escalation_policies/graphql/cache_updates.js

@@ -22,7 +22,10 @@ const addEscalationPolicyToStore = (store, query, { escalationPolicyCreate }, va
   });
 
   const data = produce(sourceData, (draftData) => {
-    draftData.project.incidentManagementEscalationPolicies.nodes.push(policy);
+    draftData.project.incidentManagementEscalationPolicies.nodes = [
+      ...draftData.project.incidentManagementEscalationPolicies.nodes,
+      policy,
+    ];
   });
 
   store.writeQuery({

ee/app/assets/javascripts/oncall_schedules/utils/cache_updates.js

@@ -22,10 +22,13 @@ const addScheduleToStore = (store, query, { oncallScheduleCreate }, variables) =
   });
 
   const data = produce(sourceData, (draftData) => {
-    draftData.project.incidentManagementOncallSchedules.nodes.push({
+    draftData.project.incidentManagementOncallSchedules.nodes = [
+      ...draftData.project.incidentManagementOncallSchedules.nodes,
+      {
         ...schedule,
         rotations: { nodes: [], __typename: ROTATION_CONNECTION_TYPE },
-    });
+      },
+    ];
   });
 
   store.writeQuery({