services: Fix anonymousOverflow redirect when answers are linked

[brian6932]

Currently, if an answer is linked in the url, the url expands to 2 ids, the first one being the thread, and the second being the answer. Anonymous Overflow at the moment, doesn't support linking to answers, you'll just get a 404 page not found, url.hashing doesn't work either (or rather, it doesn't 404, but it doesn't actually link you to the answer), this PR fixes this by grabbing the thread ID directly.
example:
https://stackoverflow.com/a/11227902
https://stackoverflow.com/questions/11227809/why-is-processing-a-sorted-array-faster-than-processing-an-unsorted-array/11227902

[ManeraKai]

Thanks :) I modified the regex a little bc it was taking the first id number where it should be taking the last id in the path.

[privacytime101]

Hi @brian6932, thanks for pointing this out. Please feel free to open an issue at the AnonymousOverflow repo for feature requests, it's not very visible here. Thanks for the redirect fix.