wallet: provide WalletBatch to 'DeleteRecords'

So it can be used within an external db txn context.

src/wallet/scriptpubkeyman.cpp

@@ -2036,9 +2036,15 @@ std::optional<MigrationData> LegacyDataSPKM::MigrateToDescriptor()
 }
 
 bool LegacyDataSPKM::DeleteRecords()
+{
+    return RunWithinTxn(m_storage.GetDatabase(), /*process_desc=*/"delete legacy records", [&](WalletBatch& batch){
+        return DeleteRecordsWithDB(batch);
+    });
+}
+
+bool LegacyDataSPKM::DeleteRecordsWithDB(WalletBatch& batch)
 {
     LOCK(cs_KeyStore);
-    WalletBatch batch(m_storage.GetDatabase());
     return batch.EraseRecords(DBKeys::LEGACY_TYPES);
 }
 

src/wallet/scriptpubkeyman.h

@@ -366,8 +366,9 @@ public:
     /** Get the DescriptorScriptPubKeyMans (with private keys) that have the same scriptPubKeys as this LegacyScriptPubKeyMan.
      * Does not modify this ScriptPubKeyMan. */
     std::optional<MigrationData> MigrateToDescriptor();
-    /** Delete all the records ofthis LegacyScriptPubKeyMan from disk*/
+    /** Delete all the records of this LegacyScriptPubKeyMan from disk*/
     bool DeleteRecords();
+    bool DeleteRecordsWithDB(WalletBatch& batch);
 };
 
 // Implements the full legacy wallet behavior

src/wallet/walletdb.cpp

@@ -1335,10 +1335,8 @@ bool WalletBatch::WriteWalletFlags(const uint64_t flags)
 
 bool WalletBatch::EraseRecords(const std::unordered_set<std::string>& types)
 {
-    return RunWithinTxn(*this, "erase records", [&types](WalletBatch& self) {
-        return std::all_of(types.begin(), types.end(), [&self](const std::string& type) {
-            return self.m_batch->ErasePrefix(DataStream() << type);
-        });
+    return std::all_of(types.begin(), types.end(), [&](const std::string& type) {
+        return m_batch->ErasePrefix(DataStream() << type);
     });
 }