[K2] Enum entry methods are not rendered

```Kotlin
enum class EnumKotlinWithMethod {
    WAITING,

    TALKING {
        fun entryOnly() = WAITING
    };
}
```
In K1, the function `entryOnly() ` is present in the function list of the entry. In K2, it missed.
But it might be by design for K2 since the function is unusable outside of the entry body.

**Installation**
- Dokka version: 1.9.20

Parent: #3328
