refactor: replace delete-button with link-action in user settings organization

[santoshchandu]

The issue number is #35015

This PR simplifies the DOM structure for the "Leave Organization" action in the user settings by replacing the form-based button with a standard link-action anchor. It also removes the redundant modal wrapper, leveraging the standard global confirm modal instead.

Changes:

Replaced the

and for leaving an organization with an tag using the .link-action class.
Updated the modal trigger from data-modal-id to data-modal-confirm.
Removed the obsolete #leave-organization modal

wrapper.
Added missing trailing newline to organization.tmpl.

[wxiaoguang]

I don't think you ever tested the change.