Consider removing the `email` property from `NorentLetterContentProps`

[sraby]

Now that we remove the user’s email from all NoRent letter content in #1395 , Should we also remove it from NorentLetterContentProps? It seems a bit moot since we will always have a user’s email at this stage, but wanted to log this issue so we can revisit.

[toolness]

Hmm, note that email is now in BaseLetterContentProps, a supertype for NorentLetterContentProps. I think this was added with the creation of EvictionFreeNY earlier this year. It may be harder to remove it now that it's part of a more generic structure, but I'm not sure.