Livepeer: enable atomic redelegation of staked LPT to another node

[kyriediculous]

What does this pull request do? Explain your changes. (required)

• Enables redelegation of staked LPT to another node within a single transaction
• Upgrades repository to hardhat v2.12.4 and smockit v2 to support arbitrum forking while testing

Specific updates (required)

• Upgrade hardhat to v2.12.4
• Upgrade smockit to v2
• Fix up tests that use mocks
• Add code to Livepeer Tenderizer to enable redelegation of funds
• Wrote a mainnet test specifically for this upgrade

How did you test each of these updates (required) Wrote an arbitrum test and ran it both against the current block and historical blocks (that have pending ETH fees)

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