[eslint-plugin] Confusing error message when a value is disallowed with `null`

**The problem**

When disallowing a property with the ESLint plugin, the error message is:

```
{property} value must be one of:
{reason}
```

While not completely incorrect, it's slightly misleading to say `value must be one of:` when there is no valid value.

Without knowing how the rule is defined, it's also possible to confuse the `{reason}` as the possible value.

**How to reproduce**

**ESLint configuration**


**Error message**


**Expected behavior**

I expect the error message to clearly indicate that the property is disallowed.

e.g.

```
Using {property} is not allowed. {reason}
```

**Environment (include versions). Did this work in previous versions?**
```
@stylexjs/eslint-plugin@0.4.1
```

---

It seems like a good first issue, so let me know if you'd like me to tackle it 🫡