Revert "FRAME: Create TransactionExtension as a replacement for SignedExtension (#2280)" (#3665)

This PR reverts #2280 which introduced `TransactionExtension` to replace
`SignedExtension`.

As a result of the discussion
[here](https://github.com/paritytech/polkadot-sdk/pull/3623#issuecomment-1986789700),
the changes will be reverted for now with plans to reintroduce the
concept in the future.

---------

Signed-off-by: georgepisaltu <george.pisaltu@parity.io>

polkadot/node/test/service/src/lib.rs

@@ -32,7 +32,7 @@ use polkadot_service::{
 	Error, FullClient, IsParachainNode, NewFull, OverseerGen, PrometheusConfig,
 };
 use polkadot_test_runtime::{
-	ParasCall, ParasSudoWrapperCall, Runtime, SignedPayload, SudoCall, TxExtension,
+	ParasCall, ParasSudoWrapperCall, Runtime, SignedExtra, SignedPayload, SudoCall,
 	UncheckedExtrinsic, VERSION,
 };
 
@@ -382,7 +382,7 @@ pub fn construct_extrinsic(
 	let period =
 		BlockHashCount::get().checked_next_power_of_two().map(|c| c / 2).unwrap_or(2) as u64;
 	let tip = 0;
-	let tx_ext: TxExtension = (
+	let extra: SignedExtra = (
 		frame_system::CheckNonZeroSender::<Runtime>::new(),
 		frame_system::CheckSpecVersion::<Runtime>::new(),
 		frame_system::CheckTxVersion::<Runtime>::new(),
@@ -391,11 +391,10 @@ pub fn construct_extrinsic(
 		frame_system::CheckNonce::<Runtime>::from(nonce),
 		frame_system::CheckWeight::<Runtime>::new(),
 		pallet_transaction_payment::ChargeTransactionPayment::<Runtime>::from(tip),
-	)
-		.into();
+	);
 	let raw_payload = SignedPayload::from_raw(
 		function.clone(),
-		tx_ext.clone(),
+		extra.clone(),
 		(
 			(),
 			VERSION.spec_version,
@@ -412,7 +411,7 @@ pub fn construct_extrinsic(
 		function.clone(),
 		polkadot_test_runtime::Address::Id(caller.public().into()),
 		polkadot_primitives::Signature::Sr25519(signature.clone()),
-		tx_ext.clone(),
+		extra.clone(),
 	)
 }