util: add TransactionError includes and namespace declarations

Add TransactionError to node namespace and include it directly instead of
relying on indirect include through common/messages.h

This is a followup to a previous commit which moved the TransactionError enum.
These changes were done in a separate followup just to keep the previous commit
more minimal and easy to review.

src/interfaces/node.h

@@ -30,10 +30,10 @@ class RPCTimerInterface;
 class UniValue;
 class Proxy;
 enum class SynchronizationState;
-enum class TransactionError;
 struct CNodeStateStats;
 struct bilingual_str;
 namespace node {
+enum class TransactionError;
 struct NodeContext;
 } // namespace node
 namespace wallet {
@@ -208,7 +208,7 @@ public:
     virtual std::optional<Coin> getUnspentOutput(const COutPoint& output) = 0;
 
     //! Broadcast transaction.
-    virtual TransactionError broadcastTransaction(CTransactionRef tx, CAmount max_tx_fee, std::string& err_string) = 0;
+    virtual node::TransactionError broadcastTransaction(CTransactionRef tx, CAmount max_tx_fee, std::string& err_string) = 0;
 
     //! Get wallet loader.
     virtual WalletLoader& walletLoader() = 0;

src/interfaces/wallet.h

@@ -35,6 +35,9 @@ struct bilingual_str;
 namespace common {
 enum class PSBTError;
 } // namespace common
+namespace node {
+enum class TransactionError;
+} // namespace node
 namespace wallet {
 class CCoinControl;
 class CWallet;