grandpa: report equivocations with unsigned extrinsics (#6656)

* grandpa: use unsigned extrinsics for equivocation reporting

* grandpa: allow signed reports as well

* grandpa: change runtime api for submitting unsigned extrinsics

* grandpa: fix tests

* grandpa: add test for unsigned validation

* grandpa: add benchmark for equivocation proof checking

* offences: fix grandpa benchmark

* grandpa: add proper weight for equivocation reporting extrinsic

* grandpa: fix weight unit

substrate/bin/utils/subkey/src/main.rs

@@ -725,7 +725,6 @@ fn create_extrinsic<C: Crypto>(
 			frame_system::CheckNonce::<Runtime>::from(i),
 			frame_system::CheckWeight::<Runtime>::new(),
 			pallet_transaction_payment::ChargeTransactionPayment::<Runtime>::from(f),
-			pallet_grandpa::ValidateEquivocationReport::<Runtime>::new(),
 		)
 	};
 	let raw_payload = SignedPayload::from_raw(
@@ -739,7 +738,6 @@ fn create_extrinsic<C: Crypto>(
 			(),
 			(),
 			(),
-			(),
 		),
 	);
 	let signature = raw_payload.using_encoded(|payload| signer.sign(payload)).into_runtime();