free_busy_report() explicitly handles [reporting] max_freebusy_occurrence = 0
as "limit disabled" when fetching occurrences (n=0 lets time_range_fill
return all occurrences), but the subsequent limit check
'len(occurrences) >= max_occurrence' is trivially true for
max_occurrence == 0, so every free-busy query on a non-empty calendar
raised ValueError ("FREEBUSY occurrences limit of 0 hit") and was
answered with HTTP 400.
Skip the limit check when the limit is disabled, consistent with how
xml_report() treats the same setting ('if max_occurrence and ...').
Behavior for positive limits is unchanged.
Co-Authored-By: Claude <noreply@anthropic.com>
f38688456d