Backport !5765 - Proto: update [delegated_balance] rpc
Context
!5765 (merged) is required in protocol Kathmandu. Cherry-picked commit from it using the following commands.
$ git checkout -b proto-k-backport-5765
$ git cherry-pick f8ba77ff7e431f76bacf07a3229a0d58fcfb10dd
Manually testing the MR
Check CI.
Edited by Fedor Sheremetyev