MM-29988 - Update exising Post APIs with collapsed threads (#16503)

store/storetest/thread_store.go

@@ -69,7 +69,7 @@ func testThreadStorePopulation(t *testing.T, ss store.Store) {
 
 		newPosts, errIdx, err3 := ss.Post().SaveMultiple([]*model.Post{&o2, &o3, &o4})
 
-		olist, _ := ss.Post().Get(otmp.Id, true)
+		olist, _ := ss.Post().Get(otmp.Id, true, false, false)
 		o1 := olist.Posts[olist.Order[0]]
 
 		newPosts = append([]*model.Post{o1}, newPosts...)