Remove global lock for transaction().

Author: rkistner

lib/src/sqlite_queries.dart

@@ -164,8 +164,9 @@ mixin SqliteQueries implements SqliteWriteContext, SqliteConnection {
       return readTransaction((ctx) => callback(ctx as SqliteWriteContext),
           lockTimeout: lockTimeout);
     } else {
-      // ignore: deprecated_member_use_from_same_package
-      return writeTransaction(callback, lockTimeout: lockTimeout);
+      return lock((ctx) async {
+        return await internalWriteTransaction(ctx, callback);
+      }, lockTimeout: lockTimeout, debugContext: 'writeTransaction()');
     }
   }
 }