Various simplifications re: Serai transactions

Removes PairSigner for the pair directly.

Resets spec_version to 1.

Defines the extrinsic without its length prefix, only prefixing during publish.

substrate/client/tests/burn.rs

@@ -20,7 +20,7 @@ use serai_client::{
     primitives::{InInstruction, InInstructionWithBalance, Batch},
   },
   coins::{primitives::OutInstruction, CoinsEvent},
-  PairSigner, Serai, SeraiCoins,
+  Serai, SeraiCoins,
 };
 
 mod common;
@@ -91,7 +91,7 @@ serai_test!(
       serai,
       &serai
         .sign(
-          &PairSigner::new(pair),
+          &pair,
           &SeraiCoins::burn_with_instruction(instruction.clone()),
           0,
           Default::default(),

substrate/client/tests/common/dex.rs

@@ -1,6 +1,6 @@
 use serai_runtime::primitives::{Coin, Amount};
 
-use serai_client::{Serai, SeraiDex, PairSigner};
+use serai_client::{Serai, SeraiDex};
 use sp_core::{sr25519::Pair, Pair as PairTrait};
 
 use crate::common::tx::publish_tx;
@@ -17,7 +17,7 @@ pub async fn add_liquidity(
   let address = pair.public();
 
   let tx = serai.sign(
-    &PairSigner::new(pair),
+    &pair,
     &SeraiDex::add_liquidity(coin, coin_amount, sri_amount, Amount(1), Amount(1), address.into()),
     nonce,
     Default::default(),
@@ -39,7 +39,7 @@ pub async fn swap(
   let address = pair.public();
 
   let tx = serai.sign(
-    &PairSigner::new(pair),
+    &pair,
     &SeraiDex::swap(from_coin, to_coin, amount_in, amount_out_min, address.into()),
     nonce,
     Default::default(),

substrate/client/tests/common/tx.rs

@@ -34,7 +34,7 @@ pub async fn publish_tx(serai: &Serai, tx: &[u8]) -> [u8; 32] {
     };
 
     for transaction in block.transactions() {
-      if transaction.0 == tx[2 ..] {
+      if transaction.0 == tx {
         return block.hash();
       }
     }