Update checkstyle to 8.10.1 (#31269)

Author: tlrx

buildSrc/src/main/groovy/org/elasticsearch/gradle/precommit/PrecommitTasks.groovy

@@ -140,7 +140,7 @@ class PrecommitTasks {
             configProperties = [
                 suppressions: checkstyleSuppressions
             ]
-            toolVersion = 7.5
+            toolVersion = '8.10.1'
         }
 
         project.tasks.withType(Checkstyle) { task ->

server/src/main/java/org/elasticsearch/transport/Transports.java

@@ -37,7 +37,7 @@ public enum Transports {
      * used in assertions to make sure that we do not call blocking code from
      * networking threads.
      */
-    public static final boolean isTransportThread(Thread t) {
+    public static boolean isTransportThread(Thread t) {
         final String threadName = t.getName();
         for (String s : Arrays.asList(
                 HttpServerTransport.HTTP_SERVER_WORKER_THREAD_NAME_PREFIX,