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.go b/core/pkg/logtree/journal.go
index bffe1b5..fe6d80c 100644
--- a/core/pkg/logtree/journal.go
+++ b/core/pkg/logtree/journal.go
@@ -168,7 +168,7 @@
 
 		passed := true
 		for _, filter := range filters {
-			if !filter(cur.origin, cur.payload.severity) {
+			if !filter(cur.origin, cur.leveled.severity) {
 				passed = false
 				break
 			}
@@ -193,7 +193,7 @@
 
 		passed := true
 		for _, filter := range filters {
-			if !filter(cur.origin, cur.payload.severity) {
+			if !filter(cur.origin, cur.leveled.severity) {
 				passed = false
 				break
 			}