Fix a tokenizer issue in a rare edge case

Summary:
Ref T7689. We may not propgate the viewer down to the controls in some rendering pathways. An example is "Create Task..." on workboard columns.

Instead, move the propagation a little deeper.

Test Plan: "Create Task..." on a workboard column.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7689

Differential Revision: https://secure.phabricator.com/D12250