LearnDash LMS 4.21.3

* Fix - Resolved an issue where if the entered license key was expired, other LearnDash plugins could not be installed properly.
* Tweak - Improved accessibility for input fields in the Setup Wizard.
* Tweak - Improved accessibility for breadcrumbs.
* Tweak - Improved accessibility for course page focus mode side navigation when zoomed in.
* Tweak - Improved accessibility for headings on registration page.
* Tweak - Improved accessibility for onboarding wizard field labels.
* Tweak - Improved accessibility of heading elements in the profile shortcode.
* Tweak - Improved accessibility for course page side navigation when zoomed in.
* Tweak - Improved accessibility for alerts with a role "alert".
* Tweak - Improved accessibility for login link and modal.
* Tweak - Improved accessibility for registration form field labels.
* Tweak - Improved accessibility for registration form error messages.
* Tweak - Improved accessibility for buttons when hovered and focused.
* Tweak - Improved accessibility for assignments table on the profile page.
* Tweak - Improved accessibility for quizzes table on the profile page.
* Tweak - Improved accessibility for essays table on the profile page.
* Tweak - Improved accessibility of the comments link in the assignments and essays tables on the profile page.
* Tweak - Improved accessibility of the view statistics and view certificate links in the quizzes tables on the profile page.
* Tweak - Improved accessibility for "sorting" choice questions.
* Tweak - Improved accessibility for course pricing section.
* Tweak - Changed the payment buttons' HTML type to `button` to improve accessibility.
* Tweak - Added a redirect alert countdown to the payment form in the Registration page (classic and modern) to improve accessibility.
* Tweak - Improved accessibility when a course step is completed.
* Tweak - Improved accessibility for error messages on registration pages.
* Tweak - Improved accessibility for tooltips.
* Tweak - Added filters: `learndash_payment_form_redirect_alert_countdown`.
* Tweak - Added templates: `src/views/components/icons/drag.php`.
* Tweak - Added functions: `learndash_30_show_step_completed_alert`, `learndash_course_get_step_completion_data`, `learndash_get_step_completed_transient_data`.
* Tweak - Updated functions: `learndash_course_get_step_completion_url`, `learndash_login_failed_alert`, `learndash_mark_complete_process`, `learndash_output_registration_success_alert`.
* Tweak - Updated filters: `learndash_group_course_row_atts`, `learndash_lesson_row_atts_sample_no_access`, `learndash_lesson_row_atts`, `learndash_quiz_row_atts`.

* Security - Added more safety checks to telemetry opt-ins/opt-outs.

* Fix - Resolved an issue where if translation files were not downloaded, a PHP notice would be shown on WordPress 6.8+.
* Fix - Resolved an incompatibility with WordPress 6.8+ and the different tabbed interfaces when editing LearnDash content.
* Fix - Removed an added border from around Quiz Questions.