Replace various test ophyd-async devices function with ophyd-async helpper functions

[Relm-Arrowny]

Dodal developers have produced various useful ways to test ophyd-async devices, and we have implemented some of these functions back into ophyd-async (see function implemented.
This issue to find and replace these Dodal functions with their ophyd-async counterparts.

Acceptance Criteria

• Replacement of superseded function.