Apply suggestions from code review

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: timtebeek

src/main/java/org/openrewrite/java/migrate/guava/AbstractNoGuavaImmutableOf.java

@@ -15,9 +15,6 @@
  */
 package org.openrewrite.java.migrate.guava;
 
-import static java.util.Collections.emptyList;
-
-import java.util.ArrayList;
 import org.jspecify.annotations.Nullable;
 import org.openrewrite.ExecutionContext;
 import org.openrewrite.Option;
@@ -32,8 +29,10 @@
 import org.openrewrite.java.search.UsesJavaVersion;
 import org.openrewrite.java.search.UsesType;
 import org.openrewrite.java.tree.*;
+import org.openrewrite.marker.Markers;
+import java.util.ArrayList;
 
-import java.time.Duration;
+import static java.util.Collections.emptyList;
 import java.util.List;
 import org.openrewrite.marker.Markers;