crypto: remove batch verification flag

[id-ms]

Summary

On V32 we introduced the batch verification for ed25519 signatures. In order to sync all nodes on the new algorithm, we added a new consensus param field.
Since the network accepted the V32 version, we can use the new algorithm on historical signatures.

Test Plan

Run full catchup test on Testnet, betanet and main net while configuring the node the verify signatures for old blocks.

[codecov-commenter]

Codecov Report

Merging #3781 (00abc08) into master (5925aff) will increase coverage by 4.68%.
The diff coverage is 88.46%.

@@            Coverage Diff             @@
##           master    #3781      +/-   ##
==========================================
+ Coverage   49.80%   54.49%   +4.68%     
==========================================
  Files         409      390      -19     
  Lines       68929    48411   -20518     
==========================================
- Hits        34332    26382    -7950     
+ Misses      30891    19803   -11088     
+ Partials     3706     2226    -1480     

Impacted Files	Coverage Δ
config/consensus.go	85.62% <ø> (-0.05%)	⬇️
node/netprio.go	0.00% <0.00%> (ø)
data/transactions/verify/txn.go	44.88% <50.00%> (+0.73%)	⬆️
agreement/vote.go	81.81% <100.00%> (ø)
crypto/batchverifier.go	100.00% <100.00%> (+9.37%)	⬆️
crypto/curve25519.go	61.81% <100.00%> (+0.80%)	⬆️
crypto/multisig.go	45.34% <100.00%> (ø)
crypto/onetimesig.go	75.86% <100.00%> (+4.08%)	⬆️
data/transactions/logic/eval.go	89.55% <100.00%> (ø)
network/wsPeer.go	65.83% <0.00%> (-2.23%)	⬇️
... and 25 more

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[jannotti]

I'm assuming that someone else (maybe @cce ?) has reviewed the work that went into making sure this PR is safe (where we looked at all past verifies). But judging this just for removing the enable flag, this looks good.

[algorandskiy]

Given the node was caught up from block 1 to the latest under extended verification settings, looks good to go.

[cce]

LGTM, I guess I should close #3783 since it is asserting both cases of EnableBatchVerification when true and false?