fix(image) Confirmation modal on builder output view EE-816 (#5114)

Co-authored-by: Simon Meng <simon.meng@portainer.io>

app/docker/views/images/build/buildImageController.js

@@ -79,6 +79,7 @@ angular.module('portainer.docker').controller('BuildImageController', [
             Notifications.error('An error occured during build', { msg: 'Please check build logs output' });
           } else {
             Notifications.success('Image successfully built');
+            $scope.state.isEditorDirty = false;
           }
         })
         .catch(function error(err) {