fix(load-task): ensure final bash is invoked as 'worker' user

Author: ahal

src/taskgraph/docker.py

@@ -316,7 +316,7 @@ def load_task(task_id, remove=True):
             image_tag,
             "bash",
             "-c",
-            f"{shlex.join(command)} && cd $TASK_WORKDIR && bash",
+            f"{shlex.join(command)} && cd $TASK_WORKDIR && su -p worker",
         ]
 
         if remove:

test/test_docker.py

@@ -158,7 +158,7 @@ def test_load_task(run_load_task):
         "-c",
         "/usr/bin/run-task --repo-checkout=/builds/worker/vcs/repo "
         "--task-cwd=/builds/worker/vcs/repo -- echo 'Task setup complete!\n"
-        "Run `exec-task` to execute the task'\"'\"'s command.' && cd $TASK_WORKDIR && bash",
+        "Run `exec-task` to execute the task'\"'\"'s command.' && cd $TASK_WORKDIR && su -p worker",
     ]
 
     mocks["subprocess_run"].assert_called_once()