Add automated test for "Create a Nested Document without creating the parents"

The manual test is here: Create a Nested Document without creating the parents

Existing automated coverage

• CreatePageNestedDocumentsIT#createNestedDocumentsFromURL: Creates nested pages from the URL (view missing page > edit to create > save), including A/B/C/D/E/F/G and X/Y where F and X are never created; asserts breadcrumb, title and reference of the created page.

Missing automated coverage

• Create xwiki/bin/view/1/2/3/4/5/6/7/8/9/ from the URL (or reuse the A/.../F/G and X/Y cases)
• Assert that none of the parent pages (1, 1/2, ... 1/2/3/4/5/6/7/8, or F and X) exist after the child page is saved

Suggested location: xwiki-platform-core/xwiki-platform-flamingo/xwiki-platform-flamingo-skin/xwiki-platform-flamingo-skin-test/xwiki-platform-flamingo-skin-test-docker/src/test/it/org/xwiki/flamingo/test/docker/CreatePageNestedDocumentsIT.java

Found by comparing the XWiki 18.4.4 manual test runs against the automated tests on master (a0055f10a1a).