Adapt to change of casing of fields in `DuplicateVoteEvidence` and `LightClientAttackEvidence` in CometBFT v1

[romac]

Description

This only impacts CometBFT v1.x

See cometbft/cometbft#3543

[melekes]

I'd like to note that this is optional. I.e. serde can support both invariants.