change SLO check notification channel to apm-java-ops-bot (#10215)

Author: igoragoli

.gitlab/macrobenchmarks.yml

@@ -143,4 +143,4 @@ notify-slo-breaches:
       when: never
     - when: always
   variables:
-    CHANNEL: "apm-java"
+    CHANNEL: "apm-java-ops-bot"