docs: remove dead link in langchain docs

[TC-MO]

The link in question was constantly throwing 404's and I cannot find anything similar in langchain docs anymore

[jirispilka]

oh, I see, they keep changing the docs structure

Alternatively, we can add this link to the apify_dataset instead (if you want).

https://python.langchain.com/docs/integrations/document_loaders/apify_dataset

(I'm not able to do suggestion on deleted line)

[TC-MO]

I'll add the link you shared to the doc instead of just deleting the 404 one and will merge this PR, thank you!