Querying delegation with non-existent validator address causes CLI to panic

[gin]

Summary of Bug

Querying delegation with non-existent validator address causes CLI to panic
Running on 0.23.1-23e3d5ac

Related to #1831 and #870

Steps to Reproduce

$ gaiacli stake delegation \
  --address-validator=cosmosaccaddr10yx3zn39va2rdvcn76cljlzn7zmlyecc7wdtvq \
  --address-delegator=cosmosaccaddr10yx3zn39va2rdvcn76cljlzn7zmlyecc7wdtvq


panic: UnmarshalBinary cannot decode empty bytes

goroutine 1 [running]:
github.com/cosmos/cosmos-sdk/x/stake/types.MustUnmarshalDelegation(0xc42082e5b0, 0xc4208b4040, 0x29, 0x40, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/x/stake/types/delegation.go:40 +0x170
github.com/cosmos/cosmos-sdk/x/stake/client/cli.GetCmdQueryDelegation.func1(0xc42084a6c0, 0xc420858300, 0x0, 0x2, 0x0, 0x0)
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/x/stake/client/cli/query.go:135 +0x2b4
github.com/cosmos/cosmos-sdk/vendor/github.com/spf13/cobra.(*Command).execute(0xc42084a6c0, 0xc4208582c0, 0x2, 0x2, 0xc42084a6c0, 0xc4208582c0)
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/vendor/github.com/spf13/cobra/command.go:698 +0x46d
github.com/cosmos/cosmos-sdk/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0x1656ce0, 0xde9b47, 0x24, 0xc4207f1898)
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/vendor/github.com/spf13/cobra/command.go:783 +0x2e4
github.com/cosmos/cosmos-sdk/vendor/github.com/spf13/cobra.(*Command).Execute(0x1656ce0, 0xc420858180, 0x1656dc0)
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/vendor/github.com/spf13/cobra/command.go:736 +0x2b
github.com/cosmos/cosmos-sdk/vendor/github.com/tendermint/tendermint/libs/cli.Executor.Execute(0x1656ce0, 0xf33510, 0x2, 0xc4207e7da0)
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/vendor/github.com/tendermint/tendermint/libs/cli/setup.go:89 +0x4e
main.main()
        /home/luigi/go/src/github.com/cosmos/cosmos-sdk/cmd/gaia/cmd/gaiacli/main.go:146 +0xb88

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For Admin Use

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

[alexanderbez]

Reference: #1831. This will be fixed with whatever PR resolves that. This should be resolved shortly 👍

[rigelrozanski]

thanks for submitting this bug report! :)

[alexanderbez]

@alessio you're tackling this via alessio/1831-avoid-panic-on-unbond-begin? Ideally we should tackle all of these at once. i.e. not panic when the validator does not exist and the like.

[alessio]

@alexanderbez Yes, I'll handle this as well