[v3-0-test] Log when triggerer has reached the maximum trigger capacity (#54536) (#54549)

Might help to know that a triggerer has reached the maximum number
of triggers it can run
(cherry picked from commit 86063eb)

Co-authored-by: Ephraim Anierobi <[email protected]>

Author: github-actions[bot]

airflow-core/src/airflow/models/trigger.py

@@ -316,6 +316,11 @@ def assign_unassigned(
         capacity -= count
 
         if capacity <= 0:
+            log.info(
+                "Triggerer %s has reached the maximum capacity triggers assigned (%d). Not assigning any more triggers",
+                triggerer_id,
+                count,
+            )
             return
 
         alive_triggerer_ids = select(Job.id).where(