Fixed checkstyle violations

dspace-server-webapp/src/main/java/org/dspace/app/rest/ShibbolethRestController.java

@@ -9,7 +9,6 @@ package org.dspace.app.rest;
 
 import java.io.IOException;
 import java.util.Arrays;
-
 import javax.servlet.http.HttpServletResponse;
 
 import org.dspace.app.rest.model.AuthnRest;

dspace-server-webapp/src/main/java/org/dspace/app/rest/security/ShibbolethAuthenticationFilter.java

@@ -9,7 +9,6 @@ package org.dspace.app.rest.security;
 
 import java.io.IOException;
 import java.util.ArrayList;
-
 import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;

dspace-server-webapp/src/main/java/org/dspace/app/rest/security/jwt/JWTTokenRestAuthenticationServiceImpl.java

@@ -12,7 +12,6 @@ import java.sql.SQLException;
 import java.text.ParseException;
 import java.util.Iterator;
 import java.util.List;
-
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

dspace-server-webapp/src/test/java/org/dspace/app/rest/AuthenticationRestControllerIT.java

@@ -21,7 +21,6 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 
 import java.util.Base64;
-
 import javax.servlet.http.Cookie;
 
 import org.dspace.app.rest.builder.GroupBuilder;