return the rewards amount on withdraw tx responses

[fedekunze]

Summary

Displaying fees on clients obtained from reward withdrawal txs is not supported because the message doesn't have an amount field.

Problem Definition

See: luniehq/lunie#2222

Proposal

return the amount withdrawn by adding it to the response message

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AC:

• Have WithdrawDelegationRewards return the rewards withdrawn
• Update handleMsgWithdrawDelegatorReward to include these rewards in a tag

cc: @alexanderbez

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For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged
• Contributor assigned/self-assigned

[alexanderbez]

So we won't be able to return the amount as a result of the tx. I think we can do one of the following:

1. Use the QueryDelegatorTotalRewards query as the amount (right before you invoke a withdraw)
2. Add a tag for amount on the tx that you can then query

[fedekunze]

Can 1 and 2 results differ ? I think 2 is more accurate, right ?

[alexanderbez]

I guess it's possible but unlikely. Yes (2) would be more ideal.

[fedekunze]

even if it's not ideal to parse the amount from the tag, I prefer to have the consistency of the amount withdrawn, so I'd go with 2.

cc: @cosmos/cosmos-ui

[faboweb]

We can add it as a tag and return it in the actual response of the REST endpoint