fix: Remove the redundant imports

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

Author: sunyuhan1998

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

@@ -28,8 +28,6 @@
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.Resource;
 
-import java.util.HashMap;
-import java.util.Map;
 import java.util.Set;
 
 import static org.assertj.core.api.Assertions.assertThat;