fix(event_listeners): do not add content length 0 to bodyless request methods

[kuhe]

Do not add content length 0 header to GET, DELETE, TRACE, OPTIONS, and HEAD requests.

• [x] add/fix unit tests

Checklist

• [x] npm run test passes
• n/a .d.ts file is updated
• [x] changelog is added, npm run add-change
• [x] run bundle exec rake docs:api and inspect doc/latest/index.html if documentation is changed
• n/a run npm run integration if integration test is changed
• n/a non-code related change (markdown/git settings etc)