GCS - Confirm Preview feature compatability

We should confirm, once the Data Lake GCS backend is up and working, that the Preview feature is also working as expected.

- Searches can be run on various timescales, on various streams.

- The function for retrieving specific messages still works:


- The function for opening a normal retrieval modal still works:


- The function for adding additional fields from the json message body to the preview message table works:


Start by bringing up the Data Lake GCS backend, then exercise the Preview feature across different timescales and streams. Verify that specific-message retrieval, the normal retrieval modal, and adding fields from a JSON message to the preview table all continue to work; completion means each listed workflow passes.

Written by the indexing model from the issue text.