Persist query params when opening a new notebook.

This broke due to changes introduced in
https://github.com/twosigma/beaker-notebook/commit/385af6959144922f083ca81d3ccf3df4ba0eae5c

which redirects the open to a session based url. Because of the redirect
we were losing the query parmas that were initially sent. The query
params contained info that was needed within a nested iframe env.