Changed INTERVAL values to be converted to milliseconds instead of
seconds, enabling users to use Superset's built-in "DURATION" number
format for human-readable display (e.g., "1d 2h 30m 45s" instead of
raw numeric values like "95445000").
This addresses the review feedback about making interval values more
user-friendly in charts while maintaining numeric operations.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>