fix: Audit fixes for Staking pool and batch nxm withdrawals

[rackstar]

Context

Closes #1209

Audit doc

There are 2 informational comments that we decided not to address, these are both on temporary functions that will be deprecated shortly after executing:

• Index out of bounds - adding validation here merely transforms "index out of bounds" error to a nicer message. Moreover, we would have fork tests to ensure that we pass the correct parameters so this error should not happen when we invoke it on main-net
• Custom Errors - it should be inconsequential if we keep it as requires specially since it will be deprecated shortly after.

Changes proposed in this pull request

• Censoring assessors by front-running - 33485ecb
• Validate IPFS hash - 2f018493
• Wrong Address - 44f40293
• Define Constants - d299b000
• Overwriting IPFS hash - 0692f728

Test plan

Add unit tests on all fixes

Checklist

• Rebased the base branch
• Attached corresponding Github issue
• Prefixed the name with the type of change (i.e. feat, chore, test)
• Performed a self-review of my own code
• Followed the style guidelines of this project
• Made corresponding changes to the documentation
• Didn't generate new warnings
• Didn't generate failures on existing tests
• Added tests that prove my fix is effective or that my feature works

Review

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