Remove Shibuya beta pallets pallet_unified_accounts & pallet_ethereum_checked

[ipapandinas]

Pull Request Summary

This PR removes 2 beta pallets only used on Shibuya: pallet_unified_accounts & pallet_ethereum_checked.

• transaction_version has been bumped to 4
• MultiAddress::Address20(h160) for an H160 that previously had a unified mapping will no longer resolve to the same AccountId32 after this change. Any balance held under the unified-mapped native account will be unreachable from the EVM after migration.
• Contracts hard-coded against extension ID 0x03 will now fail with NoChainExtension.
• Calls to the unified account 20486 precompile will now hit the EOA fallback path and silently return empty.

[ipapandinas]

/bench shibuya all

[ghost]

Benchmarks job is scheduled at https://github.com/AstarNetwork/Astar/actions/runs/26303235266.
Please wait for a while.
Branch: remove/shibuya-beta-pallets
SHA: 5fbf313

[ghost]

Benchmarks have been finished.
You can download artifacts if exists https://github.com/AstarNetwork/Astar/actions/runs/26303235266.

[ipapandinas]

/bench shibuya all

[ghost]

Benchmarks job is scheduled at https://github.com/AstarNetwork/Astar/actions/runs/26417113173.
Please wait for a while.
Branch: remove/shibuya-beta-pallets
SHA: 5fbf313

[ghost]

Benchmarks have been finished.
You can download artifacts if exists https://github.com/AstarNetwork/Astar/actions/runs/26417113173.

[ipapandinas]

/bench shibuya all

[ghost]

Benchmarks job is scheduled at https://github.com/AstarNetwork/Astar/actions/runs/26423956346.
Please wait for a while.
Branch: remove/shibuya-beta-pallets
SHA: 5fbf313

[ghost]

Benchmarks have been finished.
You can download artifacts if exists https://github.com/AstarNetwork/Astar/actions/runs/26423956346.

[Dinonard]

LGTM

I assume that removing pallet data falls within the weight limit.

[ghost]

Package	Line Rate	Branch Rate	Health
pallets/astar-xcm-benchmarks/src/generic	100%	0%	✔
pallets/democracy-mbm/src	30%	0%	❌
precompiles/dapp-staking/src/test	0%	0%	❌
precompiles/sr25519/src	69%	0%	➖
precompiles/xcm/src	70%	0%	➖
primitives/src/xcm	66%	0%	➖
pallets/dapp-staking/src/benchmarking	95%	0%	✔
primitives/src	51%	0%	➖
pallets/astar-xcm-benchmarks/src/fungible	100%	0%	✔
pallets/xc-asset-config/src	57%	0%	➖
precompiles/dapp-staking/src	89%	0%	✔
precompiles/dispatch-lockdrop/src	89%	0%	✔
pallets/inflation/src	58%	0%	➖
precompiles/assets-erc20/src	77%	0%	➖
precompiles/substrate-ecdsa/src	74%	0%	➖
pallets/astar-xcm-benchmarks/src	86%	0%	✔
pallets/collator-selection/src	82%	0%	✔
pallets/collective-proxy/src	94%	0%	✔
pallets/vesting-mbm/src	87%	0%	✔
pallets/dapp-staking/rpc/runtime-api/src	0%	0%	❌
pallets/dynamic-evm-base-fee/src	82%	0%	✔
pallets/dapp-staking/src	83%	0%	✔
pallets/dapp-staking/src/test	0%	0%	❌
Summary	74% (3465 / 4669)	0% (0 / 0)	➖

Minimum allowed line rate is 50%