I24 serial: have the PMAC program runner check the counter PV

[noemifrisina]

The collection time passed as timeout to complete on the PMAC ProgramRunner is currently calculated from the input parameters (exposure time, laser exposure and delay, number of images) plus the time needed for the PMAC moves plus a buffer. For most short experiments this works well, but for some of the longer collections, it has proven to be difficult to estimate as the buffer needed seems to increase exponentially with the number of blocks. While we should still check that the status PV (BL24I-MO-STEP-14:signal:P2401) goes to zero at the end of the collection - so tha the PMAC is not left in a weird state - we can also check when a collection is over by monitoring the counter PV (BL24I-MO-STEP-14:signal:P2402).

ProgramRunner should check that this PV has already reached the number of frames requested by timeout and if not, continue waiting.

Acceptance Criteria

• ProgramRunner doesn't complete until the counter PV reaches the expected number of frames.