fix: correct CSource-notification validator fixtures (047_10..047_15)

The shared keyword "Wait for notification and validate it" in NotificationUtils.resource carried three fixture bugs, each masking the next, so 047_10..047_15 could not pass against a conformant broker:

1. ${notification_type} read "ContextSource Notfication" (stray space + missing "i"); the type member is "ContextSourceNotification".
2. notifiedAt was checked with a fixed second-precision format (%Y-%m-%dT%H:%M:%SZ), rejecting valid RFC 3339 millisecond timestamps. Use the millis-tolerant Parse Ngsild Date instead, and drop the now-unused {date_format}/{date_format_with_millis} variables.
3. The data loop looked up the registration id as [@id]; the notification is compacted NGSI-LD JSON where the key is [id].

The broker is correct on all three. Documented as testsuite-doubts.md #75 (closed).

Co-Authored-By: Claude Opus 4.7 noreply@anthropic.com