condition property for built-in audits is undocumented

[mrajeev08]

I only noticed the nice condition property for built in audits from perusing the slack. Found reference to it in https://github.com/TobikoData/sqlmesh/issues/2399.

This isn't mentioned anywhere in the docs as far as I can see and not mentioned in the Auditing concepts page.

Is this a supported feature? If it is would be nice to have in the docs!