Need to manage the Longhorn engines upgrade

Summary

After an upgrade of Longhorn with Helm, the Longhorn manager, Longhorn UI, etc... are upgraded to the next version, but the existing Longhorn engines stay untouched by default. They can later be upgraded either manually or automatically. It seems Sylva should go with the automated process to not lag behind with some old unsupported versions of Longhorn engines.

related references

https://longhorn.io/docs/1.6.3/deploy/upgrade/upgrade-engine/

https://longhorn.io/docs/1.6.3/deploy/upgrade/auto-upgrade-engine/