XWIKI-23129: Add an end of DOM UIXP

[Sereza7]

Jira URL

https://jira.xwiki.org/browse/XWIKI-23129

Changes

Description

• Added the UIXP
• Used the UIX for one of the blocking modals for XWIKI-22669
• Handled the #exportModal and #exportTreeModal move
• Changed the nature of the modal elements to avoid overcomplicated/low reliability ARIA markup combinations.
• Updated the bootstrap style for modal to make it look as it used to with this new DOM.

Clarifications

• Since the exportModal and exportTreeModal were defined in flamingo VTL templates, I decided to just move it before the UIXP in their new template. Note that in all cases, this new template should be loaded, and it's not much of an issue if we load the modals if we don't have the buttons to open them, they stay hidden by default.
• On the opposite to a div, a dialog element has a default look (white background and black border). We update bootstrap to keep the class while updating the nature of the nodes without it impacting the looks.

Screenshots & Video

2025-04-24.10-26-02.mp4

Executed Tests

Manual tests on the three modals.
Checked the automated test paths, which is IMO the most likely thing that could have gotten broken by this:

• ExportModal:

  xwiki-platform/xwiki-platform-core/xwiki-platform-flamingo/xwiki-platform-flamingo-skin/xwiki-platform-flamingo-skin-test/xwiki-platform-flamingo-skin-test-pageobjects/src/main/java/org/xwiki/flamingo/skin/test/po/ExportModal.java

  Line 42 in bfa5b81

  super(By.id("exportModal"));

  everything is fine, the selector uses only the ID, it doesn't care about the nature or the position of the element.
• TreeExportModal: same as ExportModal
• watchModal: https://github.com/search?q=repo%3Axwiki%2Fxwiki-platform%20%23watchModal&type=code None The page object is built similarly to the export modal one

Successfully built:

• mvn clean install -f xwiki-platform-core/xwiki-platform-web/xwiki-platform-web-templates/ -Pquality
• mvn clean install -f xwiki-platform-core/xwiki-platform-web; mvn clean install -f xwiki-platform-core/xwiki-platform-notifications/xwiki-platform-notifications-ui -Pquality; mvn clean install -f xwiki-platform-core/xwiki-platform-notifications/xwiki-platform-notifications-test/xwiki-platform-notifications-test-docker (note that without building the whole xwiki-platform-web module, those tests were failing because the distrib used in the docker tests did not get the updated template)

Expected merging strategy

• Prefers squash: Yes
• Backport on branches:
  • None, this is a DOM change that applies on all pages so it's pretty dangerous.

[Sereza7]

@surli I'm assigning this one to you since you were already part of the discussion that is related to the changes proposed by this ticket and PR.