Fix DRep list UI: flex columns, warning icon, metadata verification
- Change table columns from fixed widths to flex-based layout to fill container - Fix metadataVerification field check (was using wrong field name) - Use bech32 ID as fallback when DRep has no givenName - Add truncateFormatter for long DRep IDs in list and details - Update warning icon to gray outline style, position on right side of title - Remove warning icon from details slide header