Use lower case "n" for "Tor network" in the UI
I think our convention is to capitalise it as "Tor network", but we have a few places in the browser UI that use "Tor Network".
Since this mostly effects the en-US strings, I think we can change our strings without updating their IDs. I believe weblate will notice the change in capitalisation in the source en-US string, so the relevant languages can adapt as well, but we won't loose access to the old translated strings in the mean time either.