Aura: Do not verify on state import (#13058)

* Aura: Do not verify on state import

When we import the state, we can not fetch authorities to verify the seal etc. So, we can directly
skip any verification.

* Skip checks as well for gap sync

* Update client/consensus/aura/src/import_queue.rs

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Review comment

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

substrate/client/consensus/aura/src/import_queue.rs

@@ -186,6 +186,19 @@ where
 		&mut self,
 		mut block: BlockImportParams<B, ()>,
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
+		// When importing whole state we don't verify the seal as the state is not available.
+		if block.with_state() {
+			return Ok((block, Default::default()))
+		}
+
+		// Skip checks that include execution, if being told so.
+		//
+		// This is done for example when gap syncing and it is expected that the block after the gap
+		// was checked/chosen properly, e.g. by warp syncing to this block using a finality proof.
+		if block.state_action.skip_execution_checks() {
+			return Ok((block, Default::default()))
+		}
+
 		let hash = block.header.hash();
 		let parent_hash = *block.header.parent_hash();
 		let authorities = authorities(