Description
When I use Playwright Web Scraper or Puppeteer Web Scraper, I get:

Failed to preview chunks: Error: documentStoreServices.previewChunksMiddleware - Error: documentStoreServices.previewChunks - Error: documentStoreServices.splitIntoChunks - (intermediate value) is not iterable (cannot read property undefined)

To Reproduce

1. Go to Document Stores
2. Click on 'Add Document Loader'
3. Select 'Playwright Web Scraper' or 'Puppeteer Web Scraper'
4. Fill URL: 'https://docs.flowiseai.com/getting-started'
5. Select Text Splitter: 'Recursive Character Text Splitter'
6. Click 'Preview Chunks'
7. See error: Failed to preview chunks: Error: documentStoreServices.previewChunksMiddleware - Error: documentStoreServices.previewChunks - Error: documentStoreServices.splitIntoChunks - (intermediate value) is not iterable (cannot read property undefined)

Expected behavior
I expect to see the text chunks from https://docs.flowiseai.com/getting-started

Screenshots

• Installation: Docker
• Flowise Version: 3.0.0
• OS: Windows
• Browser: Chrome

Additional context
I get the same error when using a chatflow trying to upsert to a Postgres db.