ci: Make tests run in random order

[DiamondJoseph]

Fixes #1199

Instructions to reviewer on how to test:

1. Run tests locally at least twice, ensure they are run in a random order
2. Run tests on CI, ensure they are run in a random order

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
• If changing the API for a pre-existing device, ensure that any beamlines using this device have updated their Bluesky plans accordingly
• Have the connection tests for the relevant beamline(s) been run via dodal connect ${BEAMLINE}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.90%. Comparing base (8945dea) to head (96b5870).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1201   +/-   ##
=======================================
  Coverage   97.90%   97.90%           
=======================================
  Files         183      183           
  Lines        7209     7209           
=======================================
  Hits         7058     7058           
  Misses        151      151           

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