Fix up pretalx2cfpsheet for API and add remote/in-person flag

[mxsasha]

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📚 Documentation preview 📚: https://writethedocs-www--2415.org.readthedocs.build/

[plaindocs]

Doesn't work for me:

❯ python pretalx2cfpsheet.py 
Loading current submissions from https://pretalx.com/api/events/wtd-berlin-2025/submissions/...
Traceback (most recent call last):
  File "/home/samuel/src/wtd/www/docs/_scripts/pretalx2cfpsheet.py", line 140, in <module>
    get_review_scores(
  File "/home/samuel/src/wtd/www/docs/_scripts/pretalx2cfpsheet.py", line 29, in get_review_scores
    submissions_list = load_pretalx_resource(submissions_url, http_headers)
  File "/home/samuel/src/wtd/www/docs/_scripts/pretalx2cfpsheet.py", line 130, in load_pretalx_resource
    results += response.json()['results']
KeyError: 'results'

[plaindocs]

Thanks @mxsasha