fix: Add conditional check for form ref before validating its state. (baserow#4783)

Author: jonadeline

premium/web-frontend/modules/baserow_premium/components/field/GenerateAIValuesModal.vue

@@ -226,7 +226,9 @@ export default {
       this.loading = false
     },
     valuesChanged() {
-      this.isValid = this.$refs.form.isFormValid()
+      if (this.$refs.form) {
+        this.isValid = this.$refs.form.isFormValid()
+      }
     },
   },
 }