Convert command should consider NTIA requirements

#632 already is tracking adding support for minimum NTIA requirements for SBOM generation, however, the `convert` command is not explicitly called out (but is referenced in #2197). Do we want to support changing/dropping items to make converted documents compliant? As currently (softly) proposed in https://github.com/anchore/syft/issues/632#issuecomment-2206954835 we'd like to make this behavior opt-in. This issue exists to track how that work/configuration affects the convert behavior.