[xcm-builder] Replaced deprecated CurrencyAdapter with FungibleAdapter (#3287)

I found out during the cleanup of this deprecation message in the
`polkadot-fellows` repository that we deprecated `CurrencyAdapter`
without making the recommended changes.


## TODO
- [ ] fix `polkadot-fellows` bump to 1.6.0
https://github.com/polkadot-fellows/runtimes/pull/159

---------

Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>

polkadot/xcm/pallet-xcm/src/mock.rs

@@ -30,13 +30,11 @@ use sp_core::H256;
 use sp_runtime::{traits::IdentityLookup, AccountId32, BuildStorage};
 pub use sp_std::cell::RefCell;
 use xcm::prelude::*;
-#[allow(deprecated)]
-use xcm_builder::CurrencyAdapter as XcmCurrencyAdapter;
 use xcm_builder::{
 	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom,
 	AllowTopLevelPaidExecutionFrom, Case, ChildParachainAsNative, ChildParachainConvertsVia,
 	ChildSystemParachainAsSuperuser, DescribeAllTerminal, FixedRateOfFungible, FixedWeightBounds,
-	FrameTransactionalProcessor, FungiblesAdapter, HashedDescription, IsConcrete,
+	FrameTransactionalProcessor, FungibleAdapter, FungiblesAdapter, HashedDescription, IsConcrete,
 	MatchedConvertedConcreteId, NoChecking, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, TakeWeightCredit, XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
@@ -424,9 +422,8 @@ pub type ForeignAssetsConvertedConcreteId = MatchedConvertedConcreteId<
 	JustTry,
 >;
 
-#[allow(deprecated)]
 pub type AssetTransactors = (
-	XcmCurrencyAdapter<Balances, IsConcrete<RelayLocation>, SovereignAccountOf, AccountId, ()>,
+	FungibleAdapter<Balances, IsConcrete<RelayLocation>, SovereignAccountOf, AccountId, ()>,
 	FungiblesAdapter<
 		AssetsPallet,
 		ForeignAssetsConvertedConcreteId,