Remove ⚠ Using experimental feature: tools.github guard policy (repos/min-integrity

The integrity guard feature is currently already enabled for public repos.

The user is already "using" the feature as it is already active and not really experimental. 

So suppressing it through 

```
tools:
  github:
    min-integrity: none # This workflow is allowed to examine and comment on any issues or PRs
```

should not give a warning.
