Wait for new-round events before injecting test proposals

[masih]

Several consensus tests enqueue round-N proposals before the state machine has observed the transition into round N. Under -race, those queued messages can be handled while the state is still in the previous round, so SetProposal drops the proposal and the test later times out waiting for the CompleteProposal event.

Synchronizing on the NewRound event before calling SetProposalAndBlock makes the test order match the state machine's expectations and removes the scheduler-dependent CI flake.

[github-actions]

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Apr 28, 2026, 6:03 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.17%. Comparing base (72dee5d) to head (33cddac).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3330      +/-   ##
==========================================
- Coverage   59.17%   59.17%   -0.01%     
==========================================
  Files        2097     2097              
  Lines      172485   172483       -2     
==========================================
- Hits       102067   102063       -4     
- Misses      61563    61566       +3     
+ Partials     8855     8854       -1     

Flag	Coverage Δ
sei-chain-pr	68.81% <ø> (?)
sei-db	70.41% <ø> (ø)

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see 22 files with indirect coverage changes

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