[Bug]: incorrect missed blocks key during slashing migraion (0.47 -> 0.50)

[swelf19]

Is there an existing issue for this?

• I have searched the existing issues

What happened?

slashing module.

in sdk47 missed blocks stored under the key

// ValidatorMissedBlockBitArrayPrefixKey - stored by *Consensus* address (not operator address)
func ValidatorMissedBlockBitArrayPrefixKey(v sdk.ConsAddress) []byte {
	return append(ValidatorMissedBlockBitArrayKeyPrefix, address.MustLengthPrefix(v.Bytes())...)
}

but im migration v4 code, you have copied the key with an error, you missed address.MustLengthPrefix wrapper

func validatorMissedBlockBitArrayPrefixKey(v sdk.ConsAddress) []byte {
	return append(validatorMissedBlockBitArrayKeyPrefix, v.Bytes()...)
}

it leads to no data migration in real state, and it leads to an error in the begin blocker
panic: failed to get the validator's bitmap value: failed to decode bitmap chunk; index: 93911: unexpected EOF

Cosmos SDK Version

main

How to reproduce?

1. run the node with sdk0.47
2. collect some data under missed blocks key
3. migrate node with sdk0.50