moved 2 assign statments into depth for loop after averaging loop

[sam-vizvary-QM]

The bug: These two lines are inside the n (averaging) loop but should be inside the depth loop:

assign(start, start + len_list_qua[run])
assign(run, run + 1)They advance the sequence pointer on every averaging shot instead of once per (sequence, depth) pair. This means each averaging shot plays a different circuit, and run quickly exceeds the len_list array bounds, producing bad data.

The fix: Move those two assign statements out of the for_(n, ...) loop into the for_(depth, ...) loop, and save/restore start so the same sequence replays for all averaging shots:

with for_(depth, 0, depth < len(depth_list), depth + 1):
assign(saved_start, start) # new variable, declared at program level
with for_(n, 0, n < n_avg_, n + 1):
...
play_sequence(sequence_qua, saved_start, len_list_qua[run])
...
assign(start, start + len_list_qua[run])
assign(run, run + 1)