actions: remove hardcoded gecko trust domain from retrigger-decision action (#458)

Author: jcristau

src/taskgraph/actions/retrigger.py

@@ -65,7 +65,9 @@ def retrigger_decision_action(parameters, graph_config, input, task_group_id, ta
     # absolute timestamps relative to the current time.
     task = taskcluster.get_task_definition(task_id)
     task = relativize_datestamps(task)
-    create_task_from_def(slugid(), task, parameters["level"])
+    create_task_from_def(
+        slugid(), task, parameters["level"], graph_config["trust-domain"]
+    )
 
 
 @register_callback_action(

src/taskgraph/actions/util.py

@@ -90,15 +90,15 @@ def fetch_cron(task_id):
     return (decision_task_id, full_task_graph, label_to_taskid)
 
 
-def create_task_from_def(task_id, task_def, level):
+def create_task_from_def(task_id, task_def, level, trust_domain):
     """Create a new task from a definition rather than from a label
     that is already in the full-task-graph. The task definition will
     have {relative-datestamp': '..'} rendered just like in a decision task.
     Use this for entirely new tasks or ones that change internals of the task.
     It is useful if you want to "edit" the full_task_graph and then hand
     it to this function. No dependencies will be scheduled. You must handle
     this yourself. Seeing how create_tasks handles it might prove helpful."""
-    task_def["schedulerId"] = f"gecko-level-{level}"
+    task_def["schedulerId"] = f"{trust_domain}-level-{level}"
     label = task_def["metadata"]["name"]
     session = get_session()
     create.create_task(session, task_id, label, task_def)