Algolia plugin - `transformer` function used only for the products index

Bug report

Describe the bug

When using the Algolia search plugin, only the products index will use the transformer function. I believe it should not be hardcoded and should work for any index.

System information

Medusa version (including plugins): 1.16.1, Algolia plugin 0.2.20 Node.js version: 20.8.1 Database: PostgreSQL Operating system: macOS 14.1

Steps to reproduce the behavior

Define 2 indexes, 1 for product, 1 for another entity

{
    resolve: `medusa-plugin-algolia`,
    options: {
        applicationId: process.env.ALGOLIA_APP_ID,
        adminApiKey: process.env.ALGOLIA_ADMIN_API_KEY,
        settings: {
            products: {
                indexSettings: {
                    searchableAttributes: ['title', 'description', 'material', 'tags'],
                    attributesToRetrieve: ['id', 'title', 'handle', 'thumbnail', 'subtitle', 'tags'],
                },
                transformer: (item) => ({
                    objectID: item.id,
                    title: item.title,
                    handle: item.handle,
                    thumbnail: item.thumbnail,
                    subtitle: item.subtitle,
                    tags: item.tags,
                    description: item.description,
                    material: item.material,
                }),
            },
            categories: {
                indexSettings: {
                    searchableAttributes: ['name', 'description'],
                    attributesToRetrieve: ['id', 'name', 'handle', 'thumbnail'],
                },
                transformer: (item) => {
                    return {
                        objectID: item.id,
                        name: item.name,
                        handle: item.handle,
                        thumbnail: item.thumbnail,
                        description: item.description,
                    };
                },
            },
        },
    },
}

Create entity subscriber e.g. ProductCategorySubscriber and subscribe to entity relevant event e.g. ProductCategoryService.Events.CREATED

this.eventBusService_
        .subscribe(ProductCategoryService.Events.CREATED, this.handleCategoryCreation)

handleCategoryCreation = async (data) => {
    const category = await this.productCategoryService_.retrieve(data.id);
    await this.searchService_.addDocuments(
        CATEGORY_INDEX_NAME,
        [this.transformCategory(category)],
        'categories',
    );
};

Create a relevant entity
Expected behavior

Transformer defined in the index settings is used and data is correctly transformed and indexed.

medusajs / medusa