Check block CLI command (#4240)

* Check block operation

* Update client/cli/src/lib.rs

* Update client/cli/src/params.rs

substrate/bin/node/cli/src/service.rs

@@ -568,6 +568,7 @@ mod tests {
 					auxiliary: Vec::new(),
 					fork_choice: ForkChoiceStrategy::LongestChain,
 					allow_missing_state: false,
+					import_existing: false,
 				};
 
 				block_import.import_block(params, Default::default())