Merge bitcoin/bitcoin#22337: wallet: Use bilingual_str for errors

92993aa5cf Change SignTransaction's input_errors to use bilingual_str (Andrew Chow)
171366e89b Use bilingual_str for address fetching functions (Andrew Chow)
9571c69b51 Add bilingual_str::clear() (Andrew Chow)

Pull request description:

  In a couple of places in the wallet, errors are `std::string`. In order for these errors to be translated, change them to use `bilingual_str`.

ACKs for top commit:
  hebasto:
    re-ACK 92993aa5cf, only rebased since my [previous](https://github.com/bitcoin/bitcoin/pull/22337#pullrequestreview-694542729) review, verified with
  klementtan:
    Code review ACK 92993aa5cf
  meshcollider:
    Code review ACK 92993aa5cf

Tree-SHA512: 5400e419dd87db8c49b67ed0964de2d44b58010a566ca246f2f0760ed9ef6a9b6f6df7a6adcb211b315b74c727bfe8c7d07eb5690b5922fa5828ceef4c83461f

src/test/fuzz/script_sign.cpp

@@ -13,6 +13,7 @@
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
 #include <test/fuzz/util.h>
+#include <util/translation.h>
 
 #include <cassert>
 #include <cstdint>
@@ -135,7 +136,7 @@ FUZZ_TARGET_INIT(script_sign, initialize_script_sign)
                 }
                 coins[*outpoint] = *coin;
             }
-            std::map<int, std::string> input_errors;
+            std::map<int, bilingual_str> input_errors;
             (void)SignTransaction(sign_transaction_tx_to, &provider, coins, fuzzed_data_provider.ConsumeIntegral<int>(), input_errors);
         }
     }

src/test/util/setup_common.cpp

@@ -292,7 +292,7 @@ CMutableTransaction TestChain100Setup::CreateValidMempoolTransaction(CTransactio
     input_coins.insert({outpoint_to_spend, utxo_to_spend});
     // - Default signature hashing type
     int nHashType = SIGHASH_ALL;
-    std::map<int, std::string> input_errors;
+    std::map<int, bilingual_str> input_errors;
     assert(SignTransaction(mempool_txn, &keystore, input_coins, nHashType, input_errors));
 
     // If submit=true, add transaction to the mempool.

src/test/util/wallet.cpp

@@ -8,6 +8,7 @@
 #include <outputtype.h>
 #include <script/standard.h>
 #ifdef ENABLE_WALLET
+#include <util/translation.h>
 #include <wallet/wallet.h>
 #endif
 
@@ -18,7 +19,7 @@ std::string getnewaddress(CWallet& w)
 {
     constexpr auto output_type = OutputType::BECH32;
     CTxDestination dest;
-    std::string error;
+    bilingual_str error;
     if (!w.GetNewDestination(output_type, "", dest, error)) assert(false);
 
     return EncodeDestination(dest);