By default access outbound from junos-host is always permitted so no configuration as needed to allow outbound ping from the SRX.
For inbound connections to the SRX permissions are granted based on the zone configuration under host inbound traffic. If the service or protocol is permitted by the zone setting then it allows all inbound to the SRX by default.
You only need to configure security policy with the junos-host zone if you want to override these settings to either restict outbound traffic from the default allow all. Or restrict inbound traffic by ip address instead of just protocol or service.