Update a custom field in custom plugin controller folder and reset the required fields.

controller.php

 public function actionSponsoredEntriesPriority() {
        $this->requireAdmin();
        $this->requireAjaxRequest();
        $newPriority = craft()->request->getPost('newPriority');
        $entryId = craft()->request->getPost('entryId');
        $success = false;
        $message = Craft::t('Any message from controller');

        $entries = craft()->entries;

        // update Sponsored entries 
        $entry = $entries->getEntryById($entryId);

        if ($entry != null) {
                $attrs = $entry->getContent();

                $fields = $entry->getFieldLayout()->getFields();
                $referentialFields = array();
                foreach ($fields as $layoutField) {
                    $field = $layoutField->getField();
                    if ($field->getFieldType() instanceof BaseElementFieldType) {
                        $referentialFields[$field->handle] = $entry->{$field->handle}->ids();
                    }
                }
                
                $attributes = $entry->getContent()->getAttributes();
                $measurementField = craft()->fields->getFieldByHandle('hero');
                $measurementsBlocks = [];

                // fetch all old/existing matrix blocks
                $criter = craft()->elements->getCriteria(ElementType::MatrixBlock);
                $criter->fieldId = $measurementField->id;
                $criter->ownerId = $entry->id;
                $oldBlocks = $criter->find();

                // Index them by ID
                foreach ($oldBlocks as $oldBlock) {
                  $measurementsBlocks[$oldBlock->id] = $oldBlock;
                }
                // $attributes['hero'] = $measurementsBlocks;
                // $entry->getContent()->setAttributes($attributes);

                $entry->getContent()->setAttributes(array(
                     'lightswitchFieldHandle' => 1,
                     'hero' => $measurementsBlocks
                ));

                $entry->setContentFromPost($referentialFields);
                $success = $entries->saveEntry($entry);
                $success == true;
            } else {
                //return null;
                $success = false;
        }

        // send response true/false with message
       if($success == true){
           $this->returnJson(
            array(
                'success' => $success,
                'message' => $message
            ));
       }else{
           $this->returnJson(
            array(
                'success' => $success,
                'message' => $entry->getErrors()
            ));
       }
    }