Configure emulation/linkcheck to ignore internal redirects

[parlough]

Describe the problem

The linkchecker doesn't fail when an internal link is only working because of a Firebase redirect. This hides outdated links that result in unnecessary redirects and breaks links on translated sites which don't surface our redirects at all.

Expected fix

Configure our linkcheck workflow to ignore internal redirects. Perhaps by using a different HTTP server (not Firebase emulator) that doesn't surface the redirects, or removing the redirects before emulating.

Additional context

No response