If you add a parent to a collection that is "in progress", you get an error

[julesies]

Descriptive summary

I added a batch of 100 works to JRR Test Collection. Before it finished, I went to add the JRR Test collection to another collection. I got this error.

Rationale

If this feature is not allowed, there should be a human readable error or warning

steps:

1. create a batch of works
2. before hitting save, make sure to add them to a collection
3. hit save
4. try to add a parent to the collection

[laritakr]

related to samvera/hyrax#2939

when indexing doesn’t complete, validations will fail
if you edit and save the collection that is failing (no changes necessary), it should reindex and work