Feature 8720: Get leader unit to execute action

Change-Id: I745bdadd96e7af0c4ef00fc5c0b41e71708cb489
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/n2vc/n2vc_juju_conn.py b/n2vc/n2vc_juju_conn.py
index f57b008..9230e6d 100644
--- a/n2vc/n2vc_juju_conn.py
+++ b/n2vc/n2vc_juju_conn.py
@@ -1025,7 +1025,10 @@
 
         application = await self._juju_get_application(model_name=model_name, application_name=application_name)
 
-        unit = application.units[0]
+        unit = None
+        for u in application.units:
+            if await u.is_leader_from_status():
+                unit = u
         if unit is not None:
             actions = await application.get_actions()
             if action_name in actions: