Add automated test for "Import Office Document with uncheck Filter Styles"

The manual test is here: Import Office Document with uncheck Filter Styles

Existing automated coverage

• OfficeImporterIT#verifyImport: creates a page of type "Page From Office" and imports .doc/.ppt/.xls/.odt/.odp/.ods files, checking the resulting content

Missing automated coverage

• Create a "Page From Office" page, select an office document (e.g. Test.odt and Test.doc), uncheck "Filter styles" (OfficeImporterPage#setFilterStyle(false)) and click Import
• Assert the page is created and its content is displayed properly, with style information preserved compared to the filtered import

Suggested location: xwiki-platform-core/xwiki-platform-office/xwiki-platform-office-test/xwiki-platform-office-test-docker/src/test/it/org/xwiki/officeimporter/test/ui/OfficeImporterIT.java

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