fix: google calendar sync times (system tz) (#18458) (#18459)

* fix: google calendar sync times (system tz)

* added line breaks to excessively long bit

* (chore) linter appeasement

* chore: linting

[skip ci]

(cherry picked from commit 3676188083)

Co-authored-by: PeterG <this-gavagai@users.noreply.github.com>

frappe/integrations/doctype/google_calendar/google_calendar.py

@@ -4,6 +4,7 @@
 
 from datetime import datetime, timedelta
 from urllib.parse import quote
+from zoneinfo import ZoneInfo
 
 import google.oauth2.credentials
 import requests
@@ -515,12 +516,20 @@ def google_calendar_to_repeat_on(start, end, recurrence=None):
 	Both have been mapped in a dict for easier mapping.
 	"""
 	repeat_on = {
-		"starts_on": get_datetime(start.get("date"))
-		if start.get("date")
-		else parser.parse(start.get("dateTime")).astimezone().replace(tzinfo=None),
-		"ends_on": get_datetime(end.get("date"))
-		if end.get("date")
-		else parser.parse(end.get("dateTime")).astimezone().replace(tzinfo=None),
+		"starts_on": (
+			get_datetime(start.get("date"))
+			if start.get("date")
+			else parser.parse(start.get("dateTime"))
+			.astimezone(ZoneInfo(get_time_zone()))
+			.replace(tzinfo=None)
+		),
+		"ends_on": (
+			get_datetime(end.get("date"))
+			if end.get("date")
+			else parser.parse(end.get("dateTime"))
+			.astimezone(ZoneInfo(get_time_zone()))
+			.replace(tzinfo=None)
+		),
 		"all_day": 1 if start.get("date") else 0,
 		"repeat_this_event": 1 if recurrence else 0,
 		"repeat_on": None,