Fix multiple parachain headers submission for single message delivery (#1916)

* switch off parachains relay when we don't need to relay parachains (temp solution)

* parachains relay now only works with single parachain

* fix usages of parachains relay

* revert hacky fix

* fixes

* fixed Westmint parachain ID

* fixed metrics

* fixed compilation

* fmt

* clippy

* call -> typed_state_call

bridges/relays/client-substrate/src/test_chain.rs

@@ -68,3 +68,51 @@ impl ChainWithBalances for TestChain {
 		unreachable!()
 	}
 }
+
+/// Primitives-level parachain that may be used in tests.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct TestParachainBase;
+
+impl bp_runtime::Chain for TestParachainBase {
+	type BlockNumber = u32;
+	type Hash = sp_core::H256;
+	type Hasher = sp_runtime::traits::BlakeTwo256;
+	type Header = sp_runtime::generic::Header<u32, sp_runtime::traits::BlakeTwo256>;
+
+	type AccountId = u32;
+	type Balance = u32;
+	type Index = u32;
+	type Signature = sp_runtime::testing::TestSignature;
+
+	fn max_extrinsic_size() -> u32 {
+		unreachable!()
+	}
+
+	fn max_extrinsic_weight() -> Weight {
+		unreachable!()
+	}
+}
+
+impl bp_runtime::Parachain for TestParachainBase {
+	const PARACHAIN_ID: u32 = 1000;
+}
+
+/// Parachain that may be used in tests.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct TestParachain;
+
+impl bp_runtime::UnderlyingChainProvider for TestParachain {
+	type Chain = TestParachainBase;
+}
+
+impl Chain for TestParachain {
+	const NAME: &'static str = "TestParachain";
+	const TOKEN_ID: Option<&'static str> = None;
+	const BEST_FINALIZED_HEADER_ID_METHOD: &'static str = "TestParachainMethod";
+	const AVERAGE_BLOCK_INTERVAL: Duration = Duration::from_millis(0);
+
+	type SignedBlock = sp_runtime::generic::SignedBlock<
+		sp_runtime::generic::Block<Self::Header, sp_runtime::OpaqueExtrinsic>,
+	>;
+	type Call = ();
+}