[DSSC] [DARK] Group all slow data to same aggregator

Description

Now that the DSSC uses property filtering, all slow data are recorded on the same aggregator, DA01 at both SCS and SQS, as documented here:
https://redmine.xfel.eu/issues/124712 https://redmine.xfel.eu/issues/133285

An alternative fix is to update calibration_configs/default.yaml, let me know if you'd rather have me do the changes there.
I myself prefer to do the fix here as it's a permanent change, and will be less work when updating the notebook to use extra_data.

How Has This Been Tested?

This was tested at SCS with p3423 r20.

Relevant Documents (optional)

dark_003423_r20_230330_090050.pdf shows the failure, and dark_003423_r20_230330_093832.pdf shows the effect of this change.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the code style of this project.

Reviewers

@ahmedk @schmidtp @kluyvert

Thanks!
Cyril