Use XML SBOM file rather than JSON SBOM file for extracting required

[Jasper-Ben]

Fossology currently only supports exporting the BOM as XML file, not as JSON. Since we rely on the availability of a JSON, this means that in a re-use case an additional step of converting the XML to JSON is currently needed (i.e. https://github.com/spdx/tools-java) before a newly generated SBOM can be used. While this is always done for upstream Osselot packages, for a "quick and dirty" package clearance in a fork this could be avoided.