go staking: undisable transfers for some senders

[pro-wh]

ostensibly for faucet purposes while we run the rest of the network with transfers disabled, this lets us identify a whitelist of accounts from which we allow transfers when otherwise transfers are disabled.

cc #2481

[codecov]

Codecov Report

Merging #2498 into master will increase coverage by 0.1%.
The diff coverage is 44.44%.

@@            Coverage Diff            @@
##           master    #2498     +/-   ##
=========================================
+ Coverage   67.01%   67.11%   +0.1%     
=========================================
  Files         324      324             
  Lines       29880    29887      +7     
=========================================
+ Hits        20024    20060     +36     
+ Misses       7369     7343     -26     
+ Partials     2487     2484      -3

Impacted Files	Coverage Δ
go/staking/api/api.go	50.89% <ø> (ø)	⬆️
.../consensus/tendermint/apps/staking/transactions.go	73.65% <44.44%> (-1.09%)	⬇️
go/consensus/api/grpc.go	57.02% <0%> (-6.62%)	⬇️
go/common/cbor/codec.go	64.7% <0%> (-5.89%)	⬇️
go/consensus/tendermint/tendermint.go	63.21% <0%> (-1.73%)	⬇️
go/worker/common/committee/group.go	81.04% <0%> (-1.49%)	⬇️
go/consensus/tendermint/apps/roothash/roothash.go	68.68% <0%> (-0.65%)	⬇️
go/worker/merge/committee/node.go	74.63% <0%> (-0.25%)	⬇️
go/storage/api/grpc.go	69.86% <0%> (+1.36%)	⬆️
go/worker/common/p2p/p2p.go	70.27% <0%> (+1.8%)	⬆️
... and 5 more

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[pro-wh]

gonna add changelog and merge. tests coming in a separate PR