UTF-8 support for non-Latin titles and dimensions

We turned on UTF-8 handling along the full query path so internationalized strings survive the round-trip.

1. The Data query service now uses UTF-8 encoding end-to-end.
2. Fixes garbled characters on Cyrillic, CJK and other non-Latin video titles and custom dimensions in breakdown and view-list responses.
3. The list-of-views query was tightened so trailing whitespace and zero-width characters don’t break grouping.
4. Applies to all metrics, views and errors endpoints without any client-side change required.