[Security Solution][Detections] Update the MITRE ATT&CK model to v11.3 (

#137122)

**Related to:** elastic/detection-rules#2073 (comment), #89876

## Summary

Here we regenerate the MITRE ATT&CK model in the code based on the official MITRE content:

- we update to the version `ATT&CK-v11.3` (see elastic/detection-rules#2073 (comment))
- this corresponds to the `https://raw.githubusercontent.com/mitre/cti/ATT&CK-v11.3/enterprise-attack/enterprise-attack.json` content

Also, this PR fixes the model regeneration script (check the comment below).