Fix TestEmitAuditEventForLargeEvents

The test relied on the fact that AppSessionRequests did not
implement TrimToMaxSize. However, now that all events are forced
to implemement TrimToMaxSize the test was always failing. To fix
a wrapper around the event was added that overrides TrimToMaxSize
that does no trimming.

lib/events/dynamoevents/dynamoevents_test.go

@@ -315,17 +315,30 @@ func TestEmitAuditEventForLargeEvents(t *testing.T) {
 		assert.Len(t, result, 1)
 	}, 10*time.Second, 500*time.Millisecond)
 
-	appReqEvent := &apievents.AppSessionRequest{
-		Metadata: apievents.Metadata{
-			Time: tt.suite.Clock.Now().UTC(),
-			Type: events.AppSessionRequestEvent,
+	appReqEvent := &testAuditEvent{
+		AppSessionRequest: apievents.AppSessionRequest{
+			Metadata: apievents.Metadata{
+				Time: tt.suite.Clock.Now().UTC(),
+				Type: events.AppSessionRequestEvent,
+			},
+			Path: strings.Repeat("A", maxItemSize),
 		},
-		Path: strings.Repeat("A", maxItemSize),
 	}
 	err = tt.suite.Log.EmitAuditEvent(ctx, appReqEvent)
 	require.ErrorContains(t, err, "ValidationException: Item size has exceeded the maximum allowed size")
 }
 
+// testAuditEvent wraps an existing AuditEvent, but overrides
+// the TrimToMaxSize to be a noop so that functionality can
+// be tested if an event exceeds the size limits.
+type testAuditEvent struct {
+	apievents.AppSessionRequest
+}
+
+func (t *testAuditEvent) TrimToMaxSize(maxSizeBytes int) apievents.AuditEvent {
+	return t
+}
+
 func TestConfig_SetFromURL(t *testing.T) {
 	useFipsCfg := Config{
 		UseFIPSEndpoint: types.ClusterAuditConfigSpecV2_FIPS_ENABLED,