Self Managed Duo Provisioning: include only highest tier if both addon products are present in the subscription

Summary

While it's not a frequent or expected occurrence, there may be times when a single subscription is sold such that it contains both Duo Pro and Duo Enterprise addons running concurrently. To eliminate any ambiguity around which product is active and available on the system in this event, the license should possibly created to include only the highest Duo tier rather than including both.

Consider this subscription as an example, along with associated license

Pro and Enterprise exist within the same effective subscription period. Decoding the above license reveals that Pro and Ent (and core which is likely necessary) are present:

:add_on_products=>{"duo_core"=>[{"quantity"=>9000, "started_on"=>"2024-08-15", "expires_on"=>"2027-08-16", "purchase_xid"=>"A-S012345678", "trial"=>false}], "duo_pro"=>[{"quantity"=>9000, "started_on"=>"2024-08-15", "expires_on"=>"2025-08-16", "purchase_xid"=>"C-12345678", "trial"=>false}], "duo_enterprise"=>[{"quantity"=>9000, "started_on"=>"2025-07-02", "expires_on"=>"2025-08-16", "purchase_xid"=>"C-12345678", "trial"=>false}]}

(purchase_xid pseudonymized by me)

It may be the case this is functionality irrelevant, but again, it would reduce ambigutity to only include the most relevant addon product

Support Priority Score: (0, -, -, -, -, -, -, -, -, -, -) => 0