[no-issue] error image resolver mimetype should not be part of datatable (#3415)

* move error image custom logic form datatable to documentlist

* change travis

* [fix-test-log] added optional function to data row interface

* [no-issue] fixed datatable tests

* [no-issue] fixing tests

lib/core/datatable/data/object-datarow.model.ts

@@ -35,4 +35,8 @@ export class ObjectDataRow implements DataRow {
     hasValue(key: string): boolean {
         return this.getValue(key) !== undefined;
     }
+
+    imageErrorResolver(event: Event): string {
+        return '';
+    }
 }