Probes don't export updated gid information for execve system call

[ekoops]

Describe the bug

For execve system calls, probes correctly export the effective user ID as uid. However, they don't export the effective group ID, which can change when the user run a set-group-ID program.

How to reproduce it

Run the execve system call on a binary having the set-group-ID bit set and belonging to a group different from the current user's one.

Expected behaviour

The probes correctly exports the effective group id and Falco uses this information to update the internal state for the process.

Screenshots

Environment

• Falco version:

0.39.1

• System info:

{
  "machine": "x86_64",
  "nodename": "ekoops-XPS-15-9530",
  "release": "6.8.0-48-generic",
  "sysname": "Linux",
  "version": "#48~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Oct  7 11:24:13 UTC 2"
}

• Cloud provider or hardware configuration:
• OS:

PRETTY_NAME="Ubuntu 22.04.5 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.5 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

• Kernel:

Linux ekoops-XPS-15-9530 6.8.0-48-generic #48~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Oct 7 11:24:13 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

• Installation method:

From source.
Additional context

[FedeDP]

/milestone next-driver