test(calendar): fix UNTIL date in fullday_until.ics fixture

Change UNTIL from 20250504T230000Z to 20250505T230000Z so it occurs
after (not before) the DTSTART date of 20250505, fixing invalid test data.

Author: KristjanESPERANTO

tests/mocks/fullday_until.ics

@@ -1,7 +1,7 @@
 BEGIN:VCALENDAR
 BEGIN:VEVENT
 DESCRIPTION:\n
-RRULE:FREQ=YEARLY;UNTIL=20250504T230000Z;INTERVAL=1;BYMONTHDAY=5;BYMONTH=5
+RRULE:FREQ=YEARLY;UNTIL=20250505T230000Z;INTERVAL=1;BYMONTHDAY=5;BYMONTH=5
 UID:040000008200E00074C5B7101A82E00800000000DAEF6ED30D9FDA01000000000000000
  010000000D37F812F0777844A93E97B96AD2D278B
 SUMMARY:Person A's Birthday