logtree: rename payload to leveledpayload

Test Plan: Refactor, covered by tests.

X-Origin-Diff: phab/D639
GitOrigin-RevId: 6c268c8b437a93c97720f110dbc9c39e95402648
diff --git a/core/pkg/logtree/journal_subscriber.go b/core/pkg/logtree/journal_subscriber.go
index 18b8124..d6a91db 100644
--- a/core/pkg/logtree/journal_subscriber.go
+++ b/core/pkg/logtree/journal_subscriber.go
@@ -55,12 +55,12 @@
 		}
 
 		for _, filter := range sub.filters {
-			if !filter(e.origin, e.payload.severity) {
+			if !filter(e.origin, e.leveled.severity) {
 				continue
 			}
 		}
 		select {
-		case sub.dataC <- &LogEntry{Payload: e.payload, DN: e.origin}:
+		case sub.dataC <- &LogEntry{LeveledPayload: e.leveled, DN: e.origin}:
 		default:
 			atomic.AddUint64(&sub.missed, 1)
 		}