[Bug]: Infection (mutation framework) cannot locate phpunit when in herd coverage

### Platform

macOS

### Operating system version

macOs Monterey 12.7.6 (21H1320)

### System architecture

Intel (x86)

### Herd Version

1.22.3

### PHP Version

PHP 8.3.27 (cli) (built: Oct 24 2025 13:00:13) (NTS clang 15.0.0)

### Bug description

First of all thanks for this great piece of software!

I am not sure if this is related to Herd or to Infection, but I thought to give it a try here.

```$ herd coverage ./vendor/bin/pest --coverage``` or ```herd coverage ./vendor/bin/phpunit --coverage-text``` execute normally, so I guess xdebug/coverage configuration are loaded just fine.

```$ herd coverage ./vendor/bin/infection``` on the other hand, returns this error: ```Unable to locate a phpunit executable on local system. Ensure that phpunit is installed and available.```

As I said, before heading to Infection for more details, any idea on why this might happens would be appreciated.

Thanks

### Steps to reproduce

_No response_

### Relevant log output

```shell
Warning: Module "herd" is already loaded in Unknown on line 0

____ ____ __ _
/ _/___ / __/__ _____/ /_(_)___ ____
/ // __ \/ /_/ _ \/ ___/ __/ / __ \/ __ \
_/ // / / / __/ __/ /__/ /_/ / /_/ / / / /
/___/_/ /_/_/ \___/\___/\__/_/\____/_/ /_/

#StandWithUkraine

Infection - PHP Mutation Testing Framework version 0.31.9

In FinderException.php line 62:

Unable to locate a phpunit executable on local system. Ensure that phpunit is installed and available.

```