Update to jQuery 1.14.1 and use the newly added option for dialog modal headings

forgot the ui in jquery ui , updated title and issue summary

I'd love to see this brought into Core. This adds some missing semantics to our work.

I'Ve updated the title and rescoped the issue proposed resolution since jquery ui 1.14.1 got updated 📌 Update all JavaScript dependencies which cause no changes Active . My initial proposed resolution by adding uiDialogTitleHeadingLevel: 1 after line 40 is wrong (tested it manually altering 11.x locally) . i was under the impression it would be a similar one liner like for adding the aria-modal functionality added for 11.0.0, but it seems not. reason is the _createWrapper method was already available in the dialog.jquery-ui.js but the _createTitlebar method is not available there yet.

Initially filed it as a task because of the need of updating jquery but the remaining step about changing the wrapping element of the title i would consider a bugfix.

Opened an initial MR. It is setting the option uiDialogTitleHeadingLevel that was newly introduced with jQuery UI 1.4.1 to 1 on dialog.showModal method. That way it is ensured that all dialogs modals have their title properly wrapped in an h1 instead of a span, the previous default. Since Drupal 11.0.0 and the update to jQuery UI 1.14.0 dialog modals got the aria-modal attribute added which ensures that all elements in the background of the dialog modal are removed from the accessibility object model, so the main or sometimes sole heading within a dialog modal is the title, and therefore it is advised to go with the h1 element for the title wrapper. In addition to that i've also set the margin for .ui-dialog .ui-dialog-titlebar .ui-dialog-title to zero, because the change to the h1 added an additional margin to the layout and by setting it to zero it readjusts it to the previous state of the design.

*@rocketeerbkw worked with me on the upstream change (https://github.com/jquery/jquery-ui/issues/2271) as well as on this issue here

I was able to fix the stylelint issue but the phpunit ones i feel unable to solve and they look from my none developer perspective unrelated? the errors show in the context of package manager and i've only added an option to a javascript file? if someone else could take a look please who is more familiar with this kind of stuff. thank you.