docs: Add missing import to BlueapiClient docs

[oliwenmandiamond]

Added missing DataEvent import to docs for BlueapiClient

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.20%. Comparing base (12dfa28) to head (e069cef).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1466   +/-   ##
=======================================
  Coverage   95.20%   95.20%           
=======================================
  Files          43       43           
  Lines        3128     3128           
=======================================
  Hits         2978     2978           
  Misses        150      150           

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[tpoliaw]

Thanks