[php-src] Issue #20745: "Casting out of range floats to int" applies to strings

Issue: https://github.com/php/php-src/issues/20745
Author: bwoebi

### Description

The following code:

```php
<?php var_dump((int) "9999999999999999999");
```

Resulted in this output:
```
PHP Warning:  The float-string "9999999999999999999" is not representable as an int, cast occurred in Command line code on line 1
int(9223372036854775807)
```

But I expected this output instead:
```
int(9223372036854775807)
```

I just updated to PHP 8.5.0 and surprisingly started seeing these warnings.

This was added with https://wiki.php.net/rfc/warnings-php-8-5#casting_out_of_range_floats_to_int, which explicitly talked about warning on non-representable floats. Not about strings. (I see the UPGADING entry got the `or strings that look like floats` added. But the RFC, what was voted on, does not.)

Now, e.g. `(int) "a"` is fine emitting `0` as expected ... but once that string is something looking like a number, it suddenly emits a warning.
This is especially problematic when accepting arbitrary user input like `(int) ($_POST['value'] ?? 0)`.

I strongly object to this behaviour on strings - on floats, it's fine (and was voted on).

### PHP Version

```plain
PHP 8.5.0
```

### Operating System

_No response_