Add support for claiming validator commission

[george-aj]

Proposed changes

Adds client functionality to be able to claim validator commissions.

Issues

Links to any issues resolved.

Types of changes

What types of changes does your code introduce?
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• Bugfix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to stop working as expected)
• Something else (e.g. tests, scripts, example, deployment, infrastructure, ...)

Checklist

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• I have read the CONTRIBUTING document.
• I have based my branch, and I am making a pull request against, the main branch.
• Checks and tests pass locally.

If applicable

• I have added tests that prove my fix is effective or that my feature works.
• I have checked that code coverage does not decrease.
• I have added/updated the documentations.

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did, what alternatives you considered, etc.