fix the bug in the DAG creation of injection memory directory
It's a follow-up to this MR: !490 (merged), which add the path to shared-memory-dir
for the injection layers. There is one job in DAG that is currently missed out: https://git.ligo.org/lscsoft/gstlal/-/blob/master/gstlal-inspiral/python/dags/layers/inspiral.py#L2139. The bug fix is to add the injection-dir into its DAG.