REST API: Remove unused DeleteParticipationIdResponse type

[winder]

Summary

Our SDK client generator was unable to handle this empty type. The type doesn't add anything so I'm removing it instead of adding a new feature to the generator.

Test Plan

N/A

[codecov-commenter]

Codecov Report

Merging #3500 (a0367f2) into master (2a96a78) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3500      +/-   ##
==========================================
- Coverage   47.69%   47.68%   -0.02%     
==========================================
  Files         370      370              
  Lines       59848    59848              
==========================================
- Hits        28544    28536       -8     
- Misses      27991    28000       +9     
+ Partials     3313     3312       -1     

Impacted Files	Coverage Δ
ledger/blockqueue.go	82.18% <0.00%> (-2.88%)	⬇️
network/wsPeer.go	65.83% <0.00%> (-2.23%)	⬇️
catchup/service.go	68.64% <0.00%> (-0.25%)	⬇️
network/wsNetwork.go	62.79% <0.00%> (-0.20%)	⬇️
ledger/acctupdates.go	66.73% <0.00%> (+1.14%)	⬆️
cmd/algoh/blockWatcher.go	80.95% <0.00%> (+3.17%)	⬆️

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