Make getTransactions and getReceipts return empty lists when blocks aren't found (#8910)

Signed-off-by: Matilda Clerke <[email protected]>

Author: Matilda-Clerke

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/query/BlockchainQueries.java

@@ -1222,15 +1222,19 @@ private List<Transaction> getTransactions(
       final Hash blockHash, final Supplier<Boolean> isQueryAlive) throws Exception {
     return BackendQuery.runIfAlive(
         "matchingLogs - getBlockBody",
-        () -> blockchain.getBlockBody(blockHash).orElseThrow().getTransactions(),
+        () ->
+            blockchain
+                .getBlockBody(blockHash)
+                .map((bb) -> bb.getTransactions())
+                .orElse(Collections.emptyList()),
         isQueryAlive);
   }
 
   private List<TransactionReceipt> getReceipts(
       final Hash blockHash, final Supplier<Boolean> isQueryAlive) throws Exception {
     return BackendQuery.runIfAlive(
         "matchingLogs - getTxReceipts",
-        () -> blockchain.getTxReceipts(blockHash).orElseThrow(),
+        () -> blockchain.getTxReceipts(blockHash).orElse(Collections.emptyList()),
         isQueryAlive);
   }