Pure parse of a Graph GraphDateTimeTimeZone to a UTC Date. Treats a missing or
UTC/Z time zone as UTC (the common case for Graph delta queries, which can be requested in UTC);
for a non-UTC named zone it parses the wall-clock string and appends Z (best-effort — production
SHOULD request UTC via the Prefer: outlook.timezone="UTC" header). Returns null on absent/invalid.
Pure parse of a Graph GraphDateTimeTimeZone to a UTC Date. Treats a missing or
UTC/Ztime zone as UTC (the common case for Graph delta queries, which can be requested in UTC); for a non-UTC named zone it parses the wall-clock string and appendsZ(best-effort — production SHOULD request UTC via thePrefer: outlook.timezone="UTC"header). Returnsnullon absent/invalid.