Need to add tests that test addition of endpoints, clusters and attributes for changes merged in #33523

[nivi-apple]

As part of this change, we need to add tests that also test addition of attributes not just deletion. The problem is there is no deterministic way to ensure that data storage has been written to. There is a timer based mechanism to do this. To get past this we need to add a test API that saves updated data to the data store on demand and we can use that for these tests to write to storage and verify updates were made.