feat: add validator by EVM address query to staking module

[rach-id]

Description

Closes: https://github.com/celestiaorg/cosmos-sdk/issues/313

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Author Checklist

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I have...

• [ ] included the correct type prefix in the PR title
• [ ] added ! to the type prefix if API or client breaking change
• [ ] targeted the correct branch (see PR Targeting)
• [ ] provided a link to the relevant issue or specification
• [ ] followed the guidelines for building modules
• [ ] included the necessary unit and integration tests
• [ ] added a changelog entry to CHANGELOG.md
• [ ] included comments for documenting Go code
• [ ] updated the relevant documentation or specification
• [ ] reviewed "Files changed" and left comments if necessary
• [ ] confirmed all CI checks have passed

Reviewers Checklist

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I have...

• [ ] confirmed the correct type prefix in the PR title
• [ ] confirmed ! in the type prefix if API or client breaking change
• [ ] confirmed all author checklist items have been addressed
• [ ] reviewed state machine logic
• [ ] reviewed API design and naming
• [ ] reviewed documentation is accurate
• [ ] reviewed tests and test coverage
• [ ] manually tested (if applicable)

[codecov-commenter]

Codecov Report

Merging #314 (e214dda) into release/v0.46.x-celestia (63bf627) will increase coverage by 0.00%. The diff coverage is 36.00%.

@@                    Coverage Diff                    @@
##           release/v0.46.x-celestia     #314   +/-   ##
=========================================================
  Coverage                     65.52%   65.52%           
=========================================================
  Files                           666      666           
  Lines                         70983    71008   +25     
=========================================================
+ Hits                          46511    46528   +17     
- Misses                        21895    21899    +4     
- Partials                       2577     2581    +4     

Impacted Files	Coverage Δ
x/staking/types/querier.go	0.00% <0.00%> (ø)
x/staking/keeper/querier.go	61.57% <42.85%> (-1.03%)	:arrow_down:

... and 1 file with indirect coverage changes