chore: use zoneinfo instead of pytz

[ttak-apphelix]

Description

pytz got deprecated in Django 4.0 && has been completely removed in Django 5.0.
Django 4.2 had provided USE_DEPRECATED_PYTZ flag for pytz support which has now been completely removed in Django 5.0 as well.
Django now uses zoneinfo by default and datetime module use this under the hood now instead of pytz

Difference between datetime.timezone and zoneinfo

datetime.timezone and the zoneinfo package are both related to handling time zones in Python, but they serve slightly different purposes and have different use cases.

datetime.timezone

This is part of the standard library in Python.
It provides a simple way to represent a fixed offset from UTC (Coordinated Universal Time).
It doesn't have information about daylight saving time (DST) or historical changes in time zones.
It's suitable for scenarios where you only need to work with a constant offset, and historical changes in time zones are not important.

zoneinfo

The zoneinfo package is introduced in Python 3.9 as part of PEP 615.
It provides a more comprehensive and accurate way to handle time zones by including historical changes, daylight saving time transitions, and more.
It uses the IANA Time Zone Database, which is regularly updated to reflect changes in time zones around the world.
This package is suitable for applications that require precise handling of time zones, especially when dealing with historical dates.

Original Issue link:
#33980

Related PR:
#37148

Since it involves multiple files changes and as suggested in the PR planning to break that PR into multiple small PR.

Smaller PR link:

• OpenEdx - chore: use zoneinfo instead of pytz #37523
• CMS - chore: use zoneinfo instead of pytz #37542
• LMS - chore: use zoneinfo instead of pytz #37568
• common - chore: use zoneinfo instead of pytz #37554
• themes and xmodule - chore: use zoneinfo instead of pytz #37562

[robrap]

Just same import order issue as other PR.