fix: guard access from layer.config.image

Author: danielroe

src/module.ts

@@ -63,7 +63,7 @@ export default defineNuxtModule<ModuleOptions>({
     for (const layer of nuxt.options._layers) {
       const isRootLayer = layer.config.rootDir === nuxt.options.rootDir
       const srcDir = isRootLayer ? nuxt.options.srcDir : layer.config.srcDir
-      const path = layer?.config.image?.dir || layer.config.dir?.public || 'public'
+      const path = (layer?.config.image && layer.config.image.dir) || layer.config.dir?.public || 'public'
 
       publicDirs.add(resolve(srcDir, path))
     }