Update EE8 to EE9 migration page with confirmed CXF to RESTEasy behaviour differences

The existing EE8→EE9 migration page at https://openliberty.io/docs/latest/reference/diff/jakarta-ee-diff.html covers several behaviour differences when migrating from jaxrs-2.1 (Apache CXF) to restfulWS-3.0 (RESTEasy). Two additional confirmed differences should be added in the same format as the existing entries.

1. UriInfo.getPath() — leading slash

jaxrs-2.1 behavior
UriInfo.getPath() returns the path of the current request relative to the base URI without a leading slash. For example, for a request to /myapp/resources/test, getPath() returns resources/test. This applies in both root resources and sub-resource locators.

restfulWS-3.0 behavior
UriInfo.getPath() returns the path with a leading slash. For the same request, getPath() returns /resources/test. This applies in both root resources and sub-resource locators.