For ease of lookup, I changed the helper to return an array with keys
corresponding to the instanceId of the shipping methods. I couldn't see
anywhere else in the codebase where the keys would have mattered.
MAILPOET-5625
This commit simplifies the logic of the 'used shipping method' segment
by removing the shipping method IDs from the queries. After some
considering, we have come to the conclusion that using just the shipping
method instance ID is enough.
[MAILPOET-4992]
This commit fixes an issue with the initial logic used to retrieve
shipping methods to build the UI of the 'used shipping method' segment.
It updates the code to properly retrieve WooCommerce shipping methods
configured for all zones. Before the code was getting just the shipping
method types and the shipping method instances.
The query that is used to get the subscribers that match this segment
will be updated in another commit.
[MAILPOET-4992]
