Multipin snapshot fix

[rtuck99]

Fixes #1727

Link to dodal PR (if required): #N/A
(remember to update pyproject.toml with the dodal commit tag if you need it for tests to pass!)

Instructions to reviewer on how to test:

1. Tests pass
2. Multipin collections perform snapshot generation instead of capturing separate snapshots

Checks for reviewer

• Would the PR title make sense to a user on a set of release notes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.03%. Comparing base (bff8d34) to head (9d71e12).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1753   +/-   ##
=======================================
  Coverage   93.03%   93.03%           
=======================================
  Files         164      164           
  Lines        8927     8931    +4     
=======================================
+ Hits         8305     8309    +4     
  Misses        622      622           

Components	Coverage Δ
i24 SSX	77.16% <ø> (ø)
hyperion	98.74% <100.00%> (+<0.01%)	⬆️
other	98.16% <ø> (ø)

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[phathaway]

Consistent with PR spec