[5.x] Fix helpBlock error with custom js validation rule (#11023)

Co-authored-by: Jason Varga <[email protected]>

resources/js/components/field-validation/Builder.vue

@@ -176,7 +176,7 @@ export default {
                 return false;
             }
 
-            let rule = _.chain(RULES)
+            let rule = _.chain(this.allRules)
                 .filter(rule => rule.value === this.selectedLaravelRule)
                 .first()
                 .value();