Update the ModalAjaxController::enableBootstrapAutomatically() to return JSON instead of int value

I've been working on addressing the issue as described, and here's a summary of the changes I made:

1. I've updated the enableBootstrapAutomatically() function to return JSON instead of an integer. This change is consistent with the recent updates made to the hookModalSubmit() method as per issue #3380924.

2. Modified the Ajax code in modal-page.js to correctly handle and act upon the new JSON response format.

Attached is the patch with the changes I've made. Feedback and further testing are appreciated!

Awesome! Thanks @tguerineau , we’ll test it and provide feedbacks

Tested and really worked fine

{"success":true}

After disabled

{"success":false,"message":"Bootstrap auto-load verification failed"}

Moved to the dev branch. Thank you so much @tguerineau

Automatically closed - issue fixed for 2 weeks with no activity.