fix Classcanbestatic (#5597)

Inner class is non-static but does not reference enclosing class

ref: https://errorprone.info/bugpattern/ClassCanBeStaticCo-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

apm-commons/apm-datacarrier/src/main/java/org/apache/skywalking/apm/commons/datacarrier/consumer/MultipleChannelsConsumer.java

@@ -110,8 +110,8 @@ public class MultipleChannelsConsumer extends Thread {
         running = false;
     }
 
-    private class Group {
-        private Channels channels;
+    private static class Group {
+        private  Channels channels;
         private IConsumer consumer;
 
         public Group(Channels channels, IConsumer consumer) {