explicitly set the bround mode to false in a test that is using generation only.

Signed-off-by: mxtartaglia <[email protected]>

Author: mxtartaglia-sl

platform-sdk/swirlds-platform-core/src/test/java/com/swirlds/platform/sync/ShadowGraphTest.java

@@ -14,6 +14,7 @@
 
 import com.swirlds.common.context.PlatformContext;
 import com.swirlds.common.test.fixtures.platform.TestPlatformContextBuilder;
+import com.swirlds.config.extensions.test.fixtures.TestConfigBuilder;
 import com.swirlds.platform.gossip.NoOpIntakeEventCounter;
 import com.swirlds.platform.gossip.shadowgraph.ReservedEventWindow;
 import com.swirlds.platform.gossip.shadowgraph.ShadowEvent;
@@ -38,6 +39,7 @@
 import java.util.stream.Stream;
 import org.hiero.base.crypto.Hash;
 import org.hiero.base.utility.test.fixtures.RandomUtils;
+import org.hiero.consensus.config.EventConfig_;
 import org.hiero.consensus.model.event.EventDescriptorWrapper;
 import org.hiero.consensus.model.event.PlatformEvent;
 import org.hiero.consensus.model.hashgraph.EventWindow;
@@ -78,8 +80,11 @@ public void setup() {
     }
 
     private void initShadowgraph(final Random random, final int numEvents, final int numNodes) {
-        final PlatformContext platformContext =
-                TestPlatformContextBuilder.create().build();
+        final PlatformContext platformContext = TestPlatformContextBuilder.create()
+                .withConfiguration(new TestConfigBuilder()
+                        .withValue(EventConfig_.USE_BIRTH_ROUND_ANCIENT_THRESHOLD, "false")
+                        .getOrCreateConfig())
+                .build();
 
         emitter = EventEmitterBuilder.newBuilder()
                 .setRandomSeed(random.nextLong())