Don't use RequestContext with render_to_string
Review Request #12054 — Created Feb. 12, 2022 and submitted
Django no longer allows passing in a
render_to_stringmethod. For the most part we had already migrated to
passing in plain dicts, but we had several template tags that were
trying to use it with the context that they received. In this case, we
can flatten that context to get a plain dict.
Ran unit tests.