Usually it's plug and play since almost every firewall rule is going to be outbound in nature, unless there's a restrictive firewall ruleset that even blocks outbound traffic. If outbound UDP/7351 to the Meraki data centers is blocked, that's the primary Meraki Cloud Communications mechanism, and with that blocked the devices (if they're up an running normally) should have fallen back to ports 80/443 to establish a backup cloud controller connection.
Was the AP previously up and running normally using the primary cloud connection and subsequently UDP/7351 was blocked? I'd consider rebooting the AP and allowing it to proceed through its normal connectivity and health checks to see if it is in fact using the backup cloud connection. Also run a packet capture on the wired side of the AP and look for traffic on UDP/7351 for example and see if it's matched by any return traffic, as opposed to seeing traffic on 80/443 between the AP and the destination IPs on your FW rules page.
If the weirdness continues, open a ticket with Meraki Support, they'll have some lower level visibility into the pass/fail state of specific firewall tests. Hope that helps!