Error handling when posthog is unable to get remote + cached feature flag

[wilson97]

See the snippet here:

posthog-python/posthog/client.py

Line 1433 in 13184e2

self.log.exception(f"[FEATURE FLAGS] Unable to get flag remotely: {e}")

First, if posthog is unable to get remote flag for whatever reason, it just prints the log: [FEATURE FLAGS] Unable to get flag remotely. It then tries to fetch the cached flag value. And if that doesn't exist, it just silently fails.

I think this should throw an exception if both the cached + remote flag values don't exist.