[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>

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-rococo/tests/snowbridge.rs

@@ -102,7 +102,7 @@ pub fn transfer_token_to_ethereum_insufficient_fund() {
 		H160::random(),
 		H160::random(),
 		DefaultBridgeHubEthereumBaseFee::get(),
-		FailedToTransactAsset("InsufficientBalance"),
+		FailedToTransactAsset("Funds are unavailable"),
 	)
 }