go/consensus/tendermint: sync-worker additionally check block timestamps

[ptrus]

Fixes: #2861

Sync-worker relies on Tendermint fast-sync to determine if the node is still
catching up. This PR adds aditional condition that the latest block is not
older than 1 minute. This prevents cases where node stops fast-syincing
before it has actually caught up.

TODO:

• although not directly testing the change itself done in this PR it would probably be good to have an E2E test that starts a client node at a later time (e.g. after 2 minutes or so), and ensures the node catches up and starts

[codecov]

Codecov Report

Merging #2873 into master will decrease coverage by 0.08%.
The diff coverage is 44.44%.

@@            Coverage Diff             @@
##           master    #2873      +/-   ##
==========================================
- Coverage   67.66%   67.58%   -0.09%     
==========================================
  Files         344      344              
  Lines       33609    33623      +14     
==========================================
- Hits        22743    22725      -18     
- Misses       7944     7972      +28     
- Partials     2922     2926       +4     

Impacted Files	Coverage Δ
go/consensus/tendermint/tendermint.go	66.32% <44.44%> (-0.44%)	⬇️
go/worker/common/host/interface.go	38.46% <0.00%> (-15.39%)	⬇️
go/consensus/tendermint/abci/state/state.go	50.00% <0.00%> (-7.70%)	⬇️
go/storage/api/root_cache.go	72.41% <0.00%> (-6.90%)	⬇️
go/storage/database/database.go	77.27% <0.00%> (-3.64%)	⬇️
go/storage/mkvs/tree.go	89.28% <0.00%> (-3.58%)	⬇️
go/storage/metrics.go	84.78% <0.00%> (-3.27%)	⬇️
go/registry/api/grpc.go	29.96% <0.00%> (-2.76%)	⬇️
go/storage/mkvs/insert.go	87.75% <0.00%> (-2.73%)	⬇️
go/consensus/tendermint/abci/mux.go	69.19% <0.00%> (-2.68%)	⬇️
... and 25 more

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