don't do too much work when transaction pool is disabled (#7753)

Signed-off-by: stefan.pingel@consensys.net <stefan.pingel@consensys.net>

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/NewPooledTransactionHashesMessageHandler.java

@@ -45,11 +45,11 @@ class NewPooledTransactionHashesMessageHandler implements EthMessages.MessageCal
 
   @Override
   public void exec(final EthMessage message) {
-    final Capability capability = message.getPeer().getConnection().capability(EthProtocol.NAME);
-    final NewPooledTransactionHashesMessage transactionsMessage =
-        NewPooledTransactionHashesMessage.readFrom(message.getData(), capability);
-    final Instant startedAt = now();
     if (isEnabled.get()) {
+      final Capability capability = message.getPeer().getConnection().capability(EthProtocol.NAME);
+      final NewPooledTransactionHashesMessage transactionsMessage =
+          NewPooledTransactionHashesMessage.readFrom(message.getData(), capability);
+      final Instant startedAt = now();
       scheduler.scheduleTxWorkerTask(
           () ->
               transactionsMessageProcessor.processNewPooledTransactionHashesMessage(

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/TransactionsMessageHandler.java

@@ -43,9 +43,10 @@ class TransactionsMessageHandler implements EthMessages.MessageCallback {
 
   @Override
   public void exec(final EthMessage message) {
-    final TransactionsMessage transactionsMessage = TransactionsMessage.readFrom(message.getData());
-    final Instant startedAt = now();
     if (isEnabled.get()) {
+      final TransactionsMessage transactionsMessage =
+          TransactionsMessage.readFrom(message.getData());
+      final Instant startedAt = now();
       scheduler.scheduleTxWorkerTask(
           () ->
               transactionsMessageProcessor.processTransactionsMessage(