fix: failing importer tests due to undefined read

src/importer.ts

@@ -232,7 +232,7 @@ export class Importer {
       const doc = this.fyo.doc.getNewDoc(this.schemaName, data, false);
       for (const schemaName in targetFieldnameMap) {
         const fieldname = targetFieldnameMap[schemaName];
-        const childTable = childTableMap[name][schemaName];
+        const childTable = childTableMap[name]?.[schemaName];
         if (!childTable) {
           continue;
         }

tests/testImporter.spec.ts

@@ -64,4 +64,4 @@ test('import SalesInvoices', async (t) => {
   );
 });
 
-closeTestFyo(fyo, __filename);
+closeTestFyo(fyo, __filename);