Bugfix/13911 order edit duplicate tabs

[i-just]

Description

On the order edit page, we’re getting both dynamic and static versions of the edit form. Each version pulls in the content tabs, so they’re essentially duplicated.

Issue 1: both static and dynamic tabs were taken into account when calculating if the tabs dropdown should be shown.
Fixed by re-initialising tabs after OrderActions had a chance to add a hidden class to the ones that should be hidden.

Issue 2: all tabs (for the static and dynamic forms) were showing in the tabs dropdown (looks like this existed in v3, too). Fixed by programmatically showing/hiding dropdown tab links depending on whether the order is being edited or not.

Issue 3 (raised by Nathaniel): when in editing mode, the “Transactions” tab was still selectable from the dropdown. Fixed by making it appear disabled, preventing pointer events and then falling back on selecting the previously selected tab if a user still somehow managed to select the “Transactions” tab from the dropdown.

All of the above is complemented by a CMS PR (craftcms/cms#13926) that skips moving focus to disabled options when navigating via keyboard.

Related issues

craftcms/cms#13911

[lukeholder]

Thanks @i-just !

[lukeholder]

I will let @nfourtythree review/merge this as he has recent experience with the order editor vue app.

[nfourtythree]

Thanks for this @i-just !