Console command build:project starts subprocess with system-default PHP instead of the runtime PHP

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Running the console command `build:project` with non-default PHP is not working as expected because the command runs sub-process `vendor/bin/codecept build` without specifying the PHP binary to run with, that in results makes the composer auto-loader utilize the default PHP binary from the system, which is not expected as we may have executed the `build:project` command with non system default PHP, eg:
```
php81 vendor/bin/mftf build:project
```

### Preconditions
No preconditions really, it's logical issues, but to see a practical problem you may use PHP 7.4 (or older) as default system PHP and install the MFTF with PHP 8.1 binary not aliased as `php` in the bash environment.

### Expected result
Successful build.

### Actual result
```
Fatal error: Composer detected issues in your platform: Your Composer dependencies require a PHP version ">= 8.1.0". You are running 7.4.29. in vendor/composer/platform_check.php on line 24

In BuildProjectCommand.php line 106:

The codecept build command failed unexpectedly. Please see the above output for more details.
```

Start at BuildProjectCommand.php around line 106 and trace how the `vendor/bin/codecept build` subprocess is launched. Reproduce with PHP 8.1 while the system `php` is 7.4, then verify that `build:project` uses the invoking runtime and completes without the Composer platform error.

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