Currently we show the diagrams that exist in memory. We instead want to no-op and return an empty array here even when some exist in memory. This is so that on web we don't show any diagrams in the list as they aren't actually persisted.

https://github.com/mongodb-js/compass/blob/1717b9593e4fd6fdd93089a1d88aa81819ecfd68/packages/compass-data-modeling/src/services/data-model-storage-in-memory.tsx#L19 

Let's make sure we have an E2E test for Compass web here (also that checks that it's an empty state after creating a diagram).