Improve ml thread termination during agent shutdown (#17889)

* Signal ML to terminate first without waiting for the threads to terminate
Add additional check if we need to stop within the per host ML processing

* Check for SERVICE_COLLECTORS running for the PREDICTION thread

* Function void param

* Function void param

src/ml/ml.cc

@@ -1220,7 +1220,7 @@ ml_detect_main(void *arg)
     heartbeat_t hb;
     heartbeat_init(&hb);
 
-    while (!Cfg.detection_stop) {
+    while (!Cfg.detection_stop && service_running(SERVICE_COLLECTORS)) {
         worker_is_idle();
         heartbeat_next(&hb, USEC_PER_SEC);
 
@@ -1230,6 +1230,9 @@ ml_detect_main(void *arg)
             if (!rh->ml_host)
                 continue;
 
+            if (!service_running(SERVICE_COLLECTORS))
+                break;
+
             ml_host_detect_once((ml_host_t *) rh->ml_host);
         }
         rrd_rdunlock();
@@ -1266,6 +1269,7 @@ ml_detect_main(void *arg)
             }
         }
     }
+    Cfg.training_stop = true;
 
     return NULL;
 }