Skip post install for windows VM creation

Windows VM creation doesn't support post install yet
- the job that creates the VM returns before the installation is done
- the post install template is Linux only right now

JIRA INFRA-877

app/tasks.py

@@ -114,7 +114,11 @@ def trigger_vm_creation(
         extra_vars=extra_vars,
         timeout=500,
     )
-    if post_job_template and not skip_post_install_job:
+    if (
+        post_job_template
+        and (not skip_post_install_job)
+        and (not vm_osversion.startswith("windows"))
+    ):
         current_user.launch_task(
             "trigger_post_install_job",
             resource="job",