Do not try to discover module dependencies for metapackages

Composer metapackages are not installed same way as other packages. With
no install location there is nothing to discover.

Starting with composer 2.5.6 the return type for
`Composer\Installer\InstallationManager::getInstallPath()` method becomes nullable.
This fixes type error produced for metapackages with defined extras.

Signed-off-by: Aleksei Khudiakov <aleksey@xerkus.pro>

src/ComponentInstaller.php

@@ -286,6 +286,12 @@ private function loadModuleClassesDependencies(PackageInterface $package): array
         $installer    = $this->composer->getInstallationManager();
         $packagePath  = $installer->getInstallPath($package);
 
+        /** @psalm-suppress TypeDoesNotContainNull Package path become nullable in composer 2.5.6 */
+        if ($packagePath === null || $packagePath === '') {
+            // Do not try to discover dependencies for metapackage and other
+            // potential package types that have no install location.
+            return [];
+        }
         $this->mapAutoloaders($package->getAutoload(), $dependencies, $packagePath);
 
         return $dependencies->getArrayCopy();