fix: Fix the import order.

Signed-off-by: Sun Yuhan <[email protected]>

Author: sunyuhan1998

spring-ai-model/src/test/java/org/springframework/ai/chat/prompt/SystemPromptTemplateTests.java

@@ -18,6 +18,7 @@
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 
 import org.junit.jupiter.api.Test;
 
@@ -28,8 +29,6 @@
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.Resource;
 
-import java.util.Set;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;