Fix og:image requests when html in a web page is over 1.megabyte

[phocks]

When truncating we were adding the chunk and then checking if it was over 1MB. This meant that it was always over 1MB with that included chunk. You need to check before adding the chunk, otherwise it will always fail. Sites like the New Yorker and Wired often have 1MB + html in their articles now (not good but what can you do).

This seems to fix a bunch of issues dealing with preview images not loading which were originally thought to be webp or avif errors: #18762 #14983 #27370 (but not all of them ie. The Guardian images seem to be having issues with a certain CDN key or something. Anyway, this should fix bunch of stuff because it won't raise the error and stop the return.)

ps. I haven't written much Ruby before so feel free to make any changes etc.

[phocks]

Hmm I'm just trying to fix the tests, but it seems they require it to reject the request? We don't want that do we?

[renchap]

This fix does not seem correct at all. I think changing line 59 of app/services/fetch_link_card_service.rb to res.truncated_body should make it work without other changes.

[phocks]

Ah yes. Thank you @renchap. I was going down a wrong rabbit hole it seems! But was kind of on the right track. I was about to suggest res.body_with_limit(2.megabytes) fixes it too, but res.truncated_body does it better. Thanks again. Will be good to have preview cards working with these sites that return more than 1MB in html.

Anyway feel free to either merge this latest commit, or just close the PR and change that line in another one. I just wanna see it fixed. It's been driving me mad.

Cheers.