Introduce 'intermediate_insert' method to hide implementation details (#12215)

Renaming from 'intermediate_take' to 'intermediate_remove'

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

@@ -587,7 +587,7 @@ mod tests {
 		RuntimeAppPublic,
 	};
 	use sp_timestamp;
-	use std::{borrow::Cow, sync::Arc};
+	use std::sync::Arc;
 
 	type AccountPublic = <Signature as Verify>::Signer;
 
@@ -733,9 +733,9 @@ mod tests {
 				let mut params = BlockImportParams::new(BlockOrigin::File, new_header);
 				params.post_digests.push(item);
 				params.body = Some(new_body);
-				params.intermediates.insert(
-					Cow::from(INTERMEDIATE_KEY),
-					Box::new(BabeIntermediate::<Block> { epoch_descriptor }) as Box<_>,
+				params.insert_intermediate(
+					INTERMEDIATE_KEY,
+					BabeIntermediate::<Block> { epoch_descriptor },
 				);
 				params.fork_choice = Some(ForkChoiceStrategy::LongestChain);