security/vuxml: add missing xmlns to body tag of

2023's vuln entry 8e20430d-a72b-11ed-a04f-40b034455553
(MinIO admin user creation from unprivileged account, CVE-2022-24842)

This fixes vxquery complaints (the line number might differ
depending on how many entries we've added to vuln/2023.xml):

Parsing failed @ line 4675:
Expected element in XHTML namespace.