Missing cli tests for staking module

[atheeshp]

Description

This add missing tests for staking cli which are absent in gaia/cli_test
Reference - #5951

closes: #XXXX

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• Targeted PR against correct branch (see CONTRIBUTING.md)
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[codecov]

Codecov Report

Merging #6347 into master will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master    #6347   +/-   ##
=======================================
  Coverage   55.72%   55.72%           
=======================================
  Files         465      465           
  Lines       27782    27782           
=======================================
  Hits        15481    15481           
  Misses      11197    11197           
  Partials     1104     1104           

[atheeshp]

@anilcse @aaronc,
We have an issue with UnmarshalBinaryBare here: https://github.com/cosmos/cosmos-sdk/blob/master/x/staking/client/cli/query.go#L402
but if we use UnmarshalJSON instead of UnmarshalBinaryBare it is giving expected output.
When we use UnmarshBinaryBare the command is returning with following error:
ERROR: proto: illegal wireType 7

[alexanderbez]

Note @atheeshp all queries and client logic use JSON over binary.

[fedekunze]

LGTM