Implement default report sorting in all report sources

Use new API from MDL-75525, to implement the same in all existing report sources (only a few were updated as part of that task)

Ensure that the default sorting for each is appropriate, and accompanying unit tests also take it into account. We can also remove code blocks such as this that account for undefined sorting of default reports during tests

Also linking to MDL-76181 in order to add sorting to existing stress tests