`getex()` edge cases allow exclusive options

[x4204]

There was an attempt at solving this in #1531, but it has some edge cases. For example:

>>> import redis
>>> r = redis.Redis()
>>> r.set('a', 'b')
True
>>> r.getex('a', ex=1000, px=1000)
b'b'
>>> r.ttl('a')
996

The call to getex() doesn't fail because extract_expire_flags() will use the first option that is not None.

It throws the exception only when the option values are unique:

>>> r.getex('a', ex=2, px=1000)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".venv/lib/python3.12/site-packages/redis/commands/core.py", line 1879, in getex
    "``ex``, ``px``, ``exat``, ``pxat``, "
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
redis.exceptions.DataError: ``ex``, ``px``, ``exat``, ``pxat``, and ``persist`` are mutually exclusive.

[petyaslavova]

Hi @x4204, thanks for reporting this :)
I hit the same yesterday, and a fix is already published as part of one of the new features: https://github.com/redis/redis-py/pull/3837/files#diff-f33d72cc2416a13d62ccc5c19b528300da34bbf5f52a36b739b16afd2dfd5e32R101

[petyaslavova]

Fixed with #3837