Add EnqueueErrorHandler option to SchedulerOpts

internal/rdb/inspect_test.go

@@ -2993,7 +2993,7 @@ func TestWriteListClearSchedulerEntries(t *testing.T) {
 			Spec:    "* * * * *",
 			Type:    "foo",
 			Payload: nil,
-			Opts:    "",
+			Opts:    nil,
 			Next:    now.Add(5 * time.Hour),
 			Prev:    now.Add(-2 * time.Hour),
 		},
@@ -3001,7 +3001,7 @@ func TestWriteListClearSchedulerEntries(t *testing.T) {
 			Spec:    "@every 20m",
 			Type:    "bar",
 			Payload: map[string]interface{}{"fiz": "baz"},
-			Opts:    "",
+			Opts:    nil,
 			Next:    now.Add(1 * time.Minute),
 			Prev:    now.Add(-19 * time.Minute),
 		},