Stake/unstake fix

[Dinonard]

Pull Request Summary

Fixes an issue where it's possible to end up with inconsistent staked amount for the ongoing era for some smart contract.

TODO

• [x] issue reproduced via tests
• [x] (init) solution implemented & tested
• [x] improved types test
  • [x] previous_staked tests
  • [x] unstake return values test
  • [x] unstake with different tuples test
• [x] change approach for unstake to return multiple tuples
• [x] remove redundant subperiod argument
• [x] implement & test migration logic

[Dinonard]

@ashutoshvarma thanks!

I was postponing to push the conflict resolution not to mess up the review, but sure, here it goes 🙂

[github-actions[bot]]

Package	Line Rate	Branch Rate	Health
chain-extensions/xvm/src	0%	0%	❌
pallets/block-rewards-hybrid/src	91%	0%	✔
pallets/dapps-staking/src/pallet	86%	0%	✔
precompiles/dapp-staking-v3/src	90%	0%	✔
precompiles/dispatch-lockdrop/src	86%	0%	✔
precompiles/xvm/src	74%	0%	➖
chain-extensions/pallet-assets/src	56%	0%	➖
precompiles/dapps-staking/src	93%	0%	✔
primitives/src	29%	0%	❌
precompiles/assets-erc20/src	81%	0%	✔
primitives/src/migrations	0%	0%	❌
chain-extensions/types/assets/src	0%	0%	❌
pallets/dapp-staking-v3/src	91%	0%	✔
pallets/unified-accounts/src	85%	0%	✔
primitives/src/xcm	65%	0%	➖
precompiles/unified-accounts/src	100%	0%	✔
precompiles/sr25519/src	64%	0%	➖
pallets/dapps-staking/src	89%	0%	✔
pallets/dapp-staking-v3/src/benchmarking	99%	0%	✔
pallets/astar-xcm-benchmarks/src	87%	0%	✔
chain-extensions/types/unified-accounts/src	0%	0%	❌
precompiles/substrate-ecdsa/src	74%	0%	➖
precompiles/xcm/src	73%	0%	➖
pallets/dapp-staking-migration/src	0%	0%	❌
pallets/xc-asset-config/src	64%	0%	➖
pallets/dapp-staking-v3/src/test	0%	0%	❌
pallets/astar-xcm-benchmarks/src/fungible	100%	0%	✔
chain-extensions/types/xvm/src	0%	0%	❌
chain-extensions/unified-accounts/src	0%	0%	❌
pallets/static-price-provider/src	58%	0%	➖
pallets/ethereum-checked/src	79%	0%	➖
pallets/xvm/src	51%	0%	➖
pallets/astar-xcm-benchmarks/src/generic	100%	0%	✔
pallets/dapp-staking-v3/rpc/runtime-api/src	0%	0%	❌
pallets/dynamic-evm-base-fee/src	92%	0%	✔
pallets/inflation/src	83%	0%	✔
precompiles/dapp-staking-v3/src/test	0%	0%	❌
pallets/collator-selection/src	91%	0%	✔
Summary	76% (4305 / 5687)	0% (0 / 0)	➖

Minimum allowed line rate is 50%