Require TokenizerControl to always have a datasource
Ref T4100. I can simplify the logic a bit here by moving some rendering into the datasources, but a few TokenizerControls currently don't have datasources.
Require datasources and always provide datasources.
- Used previously-datasourceless controls (e.g., "Add Reviewers").
- Used normal controls.
- Manually verified that no other controls are missing datasources.
Reviewed By: btrahan
Maniphest Tasks: T4100
Differential Revision: https://secure.phabricator.com/D12456