Rapid Diffs doesn't respect whitespace setting on page reload

When you set a user setting for whitespace it's not respected by Rapid Diffs.

How to reproduce

1. Open MR diffs using existing app (do not use Rapid Diffs yet)
2. Change your whitespace setting (the setting is stored in the DB)
3. Load the same page with ?rapid_diffs=true
4. Whitespace setting is not respected (it should be)