Hyperion 1169 Attempted fix for failure re-arming the detector after beam dump

[rtuck99]

Fixes DiamondLightSource/mx-bluesky#282

Instructions to reviewer on how to test:

1. To reproduce the issue without the fix, set dodal.devices.eiger.TEST_1169_INJECT = True, and dodal.devices.eiger.TEST_1169_FIX = False, this will cause the stage to be re-attempted, it should fail before it reaches the cam acquire and fan wait
2. To test whether the fix works, leave the values at their defaults - it should now successfully re-arm the detector

If the tests pass we can tidy the code.

Checks for reviewer

• Would the PR title make sense to a scientist on a set of release notes
• If a new device has been added does it follow the standards

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.79%. Comparing base (ccb4e81) to head (2956593).

❗ Current head 2956593 differs from pull request most recent head fa73693. Consider uploading reports for the commit fa73693 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main     DiamondLightSource/hyperion#410   +/-   ##
=======================================
  Coverage   92.78%   92.79%           
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  Files          99       99           
  Lines        3769     3773    +4     
=======================================
+ Hits         3497     3501    +4     
  Misses        272      272           

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[olliesilvester]

Looks sensible, let's go down to test together at some point. Could you fix the mypy error?

[DominicOram]

Merge this. @rtuck99 and @DominicOram to test tomorrow.