[link-validator] Missing file context-api.md

[simoneonofri]

Hello,

There is a note with a broken reference link.

Note: This command lets automation verify that the [context api](https://github.com/fedidcg/FedCM/blob/main/proposals/context-api.md) was applied properly

I searched inside the repo and could not find it.

I am proposing to remove it, if it not exist anymore. Otherwise feel free to modify the PR.

Thanks,

Simone

P.S. This should be the last check for publication in /TR