In T389773: Adjust maximum number of mapped tasks in the airflow instance we upped the max mapped task to 1200, but only for the test_k8s instance.
On the main instance, we have multiple DAGs that map by wiki_id, and thus currently at ~883 tasks.
Let's make that former bump a global setting that applies to all instances and proactively take care of this potential issue.
This would we needed as well for T404084: Move the dumps_v1 DAGs from the Airflow test_k8s instance to a dedicated instance.
