macos for metricbeat to run in the extended meta-stage (#26573)

(cherry picked from commit 1541b2e)

Author: v1v

metricbeat/Jenkinsfile.yml

@@ -48,6 +48,7 @@ stages:
                 - "macosTest"
             branches: true     ## for all the branches
             tags: true         ## for all the tags
+        stage: extended
     windows:
         mage: "mage build unitTest"
         platforms:             ## override default labels in this specific stage.