[PHP] Accessing Enum::value on Non Backed Enums should produce warning

### Apache NetBeans version

Apache NetBeans 16

### What happened

Enum::value will produce warning if the enum is not Backed Enums

### How to reproduce

```php
name ."\n"; // OK
echo Suit1::Clubs->value ."\n"; // this statement should display warning

$card = Suit1::Diamonds;
echo $card->name ."\n"; // OK
echo $card->value ."\n"; // this statement should display warning

// ----------------------------------

enum Suit2: string {
case Hearts = 'H';
case Diamonds = 'D';
case Clubs = 'C';
case Spades = 'S';
}

echo Suit2::Spades->name ."\n"; // OK
echo Suit2::Clubs->value ."\n"; // OK

$card2 = Suit2::Diamonds;
echo $card2->name ."\n"; // OK
echo $card2->value ."\n"; // OK
```

### Did this work correctly in an earlier version?

No / Don't know

### Operating System

Windows 10

### JDK

Java: 14.0.1; Java HotSpot(TM) 64-Bit Server VM 14.0.1+7 Runtime: Java(TM) SE Runtime Environment 14.0.1+7

### Apache NetBeans packaging

Apache NetBeans provided installer

### Anything else

_No response_

### Are you willing to submit a pull request?

No

### Code of Conduct

Yes

Use the PHP enum example in the issue as the reproduction entry point, checking both non-backed and backed enums and both direct and variable access. Confirm that accessing value on a non-backed enum produces a warning while name remains valid, and verify the corresponding diagnostic in NetBeans' PHP editor.

Written by the indexing model from the issue text.