sqldb: separate migration execution from construction

This commit separates the execution of SQL and in-code migrations
from their construction. This change is necessary because,
currently, the SQL schema is migrated during the construction
phase in the lncfg package. However, migrations are typically
executed when individual stores are constructed within the
configuration builder.

config_builder.go

@@ -932,10 +932,10 @@ type DatabaseInstances struct {
 	// the btcwallet's loader.
 	WalletDB btcwallet.LoaderOption
 
-	// NativeSQLStore is a pointer to a native SQL store that can be used
-	// for native SQL queries for tables that already support it. This may
-	// be nil if the use-native-sql flag was not set.
-	NativeSQLStore *sqldb.BaseDB
+	// NativeSQLStore holds a reference to the native SQL store that can
+	// be used for native SQL queries for tables that already support it.
+	// This may be nil if the use-native-sql flag was not set.
+	NativeSQLStore sqldb.DB
 }
 
 // DefaultDatabaseBuilder is a type that builds the default database backends
@@ -1079,6 +1079,19 @@ func (d *DefaultDatabaseBuilder) BuildDatabase(
 
 	// Instantiate a native SQL invoice store if the flag is set.
 	if d.cfg.DB.UseNativeSQL {
+		// We need to apply all migrations to the native SQL store
+		// before we can use it.
+		err := dbs.NativeSQLStore.ApplyAllMigrations(
+			ctx, sqldb.GetMigrations(),
+		)
+		if err != nil {
+			cleanUp()
+			err := fmt.Errorf("unable to apply migrations: %w", err)
+			d.logger.Error(err)
+
+			return nil, nil, err
+		}
+
 		// KV invoice db resides in the same database as the channel
 		// state DB. Let's query the database to see if we have any
 		// invoices there. If we do, we won't allow the user to start
@@ -1107,10 +1120,11 @@ func (d *DefaultDatabaseBuilder) BuildDatabase(
 			return nil, nil, err
 		}
 
+		baseDB := dbs.NativeSQLStore.GetBaseDB()
 		executor := sqldb.NewTransactionExecutor(
-			dbs.NativeSQLStore,
+			baseDB,
 			func(tx *sql.Tx) invoices.SQLInvoiceQueries {
-				return dbs.NativeSQLStore.WithTx(tx)
+				return baseDB.WithTx(tx)
 			},
 		)