--output-document isn't respected for tx multisign command

[rootulp]

Context

@adlerjohn reported a bug on Slack

Problem

Is it expected if I celestia-appd tx multisign that the --output-document flag does nothing other than create an empty file (content still gets dumped to stdout)?

Proposal

The --output-document is supposed to redirect output to a file. If output still gets dumped to stdout, this indicates a bug. Note: this may involve fixing a bug in upstream cosmos-sdk or at least our fork until it gets upstreamed.

1. Fix the bug in celestiaorg/cosmos-sdk: fix: --output-document flag for multisign cosmos-sdk#363
2. Bump the dep in this repo

[rootulp]

Reproduced the error with this snippet:

#!/bin/sh

# Stop script execution if an error is encountered
set -o errexit
# Stop script execution if an undefined variable is used
set -o nounset

# Prerequisite: prior to running this script, start a single node devnet with ./scripts/single-node.sh
CHAIN_ID="private"
KEY_NAME="validator"
KEYRING_BACKEND="test"
BROADCAST_MODE="block"

celestia-appd keys add test1
celestia-appd keys add test2
celestia-appd keys add test3
celestia-appd keys add multisig --multisig test1,test2,test3 --multisig-threshold 2

celestia-appd tx bank send $VALIDATOR $MULTISIG 100000utia --from $VALIDATOR --fees 1000utia --chain-id $CHAIN_ID --keyring-backend $KEYRING_BACKEND --broadcast-mode $BROADCAST_MODE --yes
# Uncomment the next line to verify that the multisig account received some funds
# celestia-appd query bank balances $MULTISIG

celestia-appd tx bank send $MULTISIG $VALIDATOR 1utia --from $MULTISIG --fees 1000utia --chain-id $CHAIN_ID --keyring-backend $KEYRING_BACKEND --generate-only > unsignedTx.json
celestia-appd tx sign unsignedTx.json --multisig $MULTISIG --from test1 --output-document test1sig.json --chain-id $CHAIN_ID
celestia-appd tx sign unsignedTx.json --multisig $MULTISIG --from test2 --output-document test2sig.json --chain-id $CHAIN_ID
# Uncomment the next lines to verify that the signatures were created
# cat test1sig.json | jq .
# cat test2sig.json | jq .

# BUG: this prints to stdout instead of writing to a file
celestia-appd tx multisign unsignedTx.json multisig test1sig.json test2sig.json --output-document=signedTx.json --chain-id $CHAIN_ID
celestia-appd tx multisign unsignedTx.json multisig test1sig.json test2sig.json --output-document=signedTx.json --chain-id $CHAIN_ID --generate-only

# Note: these may be helpful if you need to debug locally after running this script
# export VALIDATOR=$(celestia-appd keys show validator -a)
# export TEST1=$(celestia-appd keys show test1 -a)
# export TEST2=$(celestia-appd keys show test2 -a)
# export TEST3=$(celestia-appd keys show test3 -a)
# export MULTISIG=$(celestia-appd keys show multisig -a)

[rootulp]

Relevant

1. tx sign command output can no longer be piped to a file cosmos/cosmos-sdk#10861
2. refactor: hide --output flags that don't work cosmos/cosmos-sdk#17188