Simplify by just checking for fixture_file_upload
Simplify by just checking for fixture_file_upload

Rather than scan the source location of the method, we can just check
for #fixture_file_upload, since it would also be defined on Notice.

kylerippey/honeybadger-ruby,gtd/honeybadger-ruby,Workable/honeybadger-ruby,gtd/honeybadger-ruby,kylerippey/honeybadger-ruby,honeybadger-io/honeybadger-ruby,Workable/honeybadger-ruby,honeybadger-io/honeybadger-ruby