fix: checkstyle

Signed-off-by: LE SAULNIER Kevin <[email protected]>

Author: LE SAULNIER Kevin

src/main/java/org/gridsuite/studyconfig/server/dto/studylayout/diagramlayout/AbstractDiagramLayout.java

@@ -1,6 +1,5 @@
 package org.gridsuite.studyconfig.server.dto.studylayout.diagramlayout;
 
-import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import lombok.AllArgsConstructor;