Prevent duplicate entries in module preloads

Author: xDeSwa

src/Symfony/Component/AssetMapper/ImportMap/ImportMapRenderer.php

@@ -73,7 +73,7 @@ public function render(string|array $entryPoint, array $attributes = []): string
             if ('css' !== $data['type']) {
                 $importMap[$importName] = $path;
                 if ($preload) {
-                    $modulePreloads[] = $path;
+                    $modulePreloads[$path] = $path;
                 }
             } elseif ($preload) {
                 $cssLinks[] = $path;