CVE-2024-29905: DIRAC: Unauthorized users can read proxy contents during generation

During the proxy generation process (e.g., when using dirac-proxy-init) it is possible for unauthorized users on the same machine to gain read access to the proxy. This allows the user to then perform any action that is possible with the original proxy.

This vulnerability only exists for a short period of time (sub-millsecond) during the generation process.