test-staking-e2e: Add to main Cargo.toml. (#14062)

This ensures that it is actually tested as part of the CI. There is also no need to have it separate.

substrate/frame/election-provider-multi-phase/test-staking-e2e/src/lib.rs

@@ -34,8 +34,8 @@ macro_rules! log {
 		log::$level!(
 			target: crate::LOG_TARGET,
 			concat!("🛠️  ", $patter)  $(, $values)*
-        )
-    };
+		)
+	};
 }
 
 fn log_current_time() {

substrate/frame/election-provider-multi-phase/test-staking-e2e/src/mock.rs

@@ -125,6 +125,10 @@ impl pallet_balances::Config for Runtime {
 	type ExistentialDeposit = ExistentialDeposit;
 	type AccountStore = System;
 	type WeightInfo = ();
+	type HoldIdentifier = ();
+	type FreezeIdentifier = ();
+	type MaxHolds = traits::ConstU32<1>;
+	type MaxFreezes = traits::ConstU32<1>;
 }
 
 impl pallet_timestamp::Config for Runtime {