feat(dot/rpc): Add offchain_localStorageClear RPC method

[khssnv]

Changes

Implements new offchain_localStorageClear RPC method introduced to the Polkadot SDK in paritytech/polkadot-sdk#7266. Motivation paritytech/polkadot-sdk#7265.

Tests

go test ./... -timeout=30m -run "^(Test_OffchainModule_LocalStorageClear|TestOffchainModule_LocalStorageClear|TestOffchainRPC)$"

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[dimartiro]

Do you need help to finish this?

[khssnv]

Other t.Run instances in this test function are also marked as TODO, so I decided to add this one in the same way. Would you like to keep it as it is, implement this specific t.Run, or implement all three?

[dimartiro]

I think would be great to have at least this one implemented

[dimartiro]

@khssnv thanks for the contribution! I looks more like a draft since there are still some TODOs to finish. If that's the case, could you please convert it to a draft while you are working on it?

[khssnv]

@khssnv thanks for the contribution! I looks more like a draft since there are still some TODOs to finish. If that's the case, could you please convert it to a draft while you are working on it?

Thanks for the review! Converted to draft.