Pass relay_storage_root into ValidationParams (#2245)

Prior this commit, a PVF wasn't able to access this property.

polkadot/parachain/test-parachains/adder/collator/src/lib.rs

@@ -234,6 +234,7 @@ mod tests {
 				parent_head: parent_head.encode().into(),
 				block_data: collation.proof_of_validity.block_data,
 				relay_chain_height: 1,
+				relay_storage_root: Default::default(),
 				hrmp_mqc_heads: Vec::new(),
 				dmq_mqc_head: Default::default(),
 			},