fix: script uses app. prefix for getWidgetById sibling resolution

bricks.app.root is not a widget (no .dom_element), causing get_by_id to fail.
Use bricks.getWidgetById('app.tblname_tbl') without second arg — bricks
resolves 'app' to bricks.app automatically, then searches downward from root.

xls2ddl/tmpls.py

@@ -28,7 +28,7 @@ data_browser_tmpl = """
 		"event":"submit",
 		"actiontype":"script",
 		"target":"app.{{tblname}}_tbl",
-		"script":"var tbl = bricks.getWidgetById('{{tblname}}_tbl', bricks.app.root); if(tbl) await tbl.render(params);"
+		"script":"var tbl = bricks.getWidgetById('app.{{tblname}}_tbl'); if(tbl) await tbl.render(params);"
 	}]
 },
 {% endif %}