[php-src] Issue #23422: openssl_sign() cannot sign a precomputed digest

Issue: https://github.com/php/php-src/issues/23422
Author: timo-poppinga

### Description

## Description

`openssl_sign()` currently always performs the digest operation internally before signing the data.

This causes a problem when the input is already a precomputed digest.

For example, when a SHA-256 digest is passed to `openssl_sign()` together with `OPENSSL_ALGO_SHA256`, the digest is hashed again:

    signature = sign(SHA256(precomputed_sha256_digest))

instead of signing the existing digest directly:

    signature = sign(precomputed_sha256_digest)

As a result, PHP currently has no straightforward way to sign an already computed digest using `ext/openssl`.

## Expected behavior

It should be possible to pass a precomputed digest to the OpenSSL extension and sign it directly without applying another hashing operation.

The same should be possible for verification of a signature over a precomputed digest.

## Actual behavior

`openssl_sign()` combines hashing and signing. Therefore, when the caller already has the digest, an additional hashing operation is performed.

## Additional information

OpenSSL provides lower-level APIs such as `EVP_PKEY_sign()` and `EVP_PKEY_verify()` that can operate on already prepared input.

PHP's OpenSSL extension currently does not expose an equivalent way to perform this operation.

### PHP Version

```plain
PHP 8.5
```

### Operating System

all