fix: Handle invalid SENTRY_DEBUG values properly (#4400)

Previously, if the environment variable `SENTRY_DEBUG` would have an
invalid value, such as "invalid," we would set `rv["debug"]` to `None`.
However, since this value should be a boolean, it should instead be set
to `False`.

This change ensures that `rv["debug"]` always is a boolean. Where we
previously would have set the value to `None`, we now set it to `False`.
Other behavior remains unchanged.

Ref
https://github.com/getsentry/sentry-python/pull/4366/files#r2075294825

Author: szokeasaurusrex

sentry_sdk/client.py

@@ -110,7 +110,7 @@ def _get_options(*args, **kwargs):
         rv["environment"] = os.environ.get("SENTRY_ENVIRONMENT") or "production"
 
     if rv["debug"] is None:
-        rv["debug"] = env_to_bool(os.environ.get("SENTRY_DEBUG", "False"), strict=True)
+        rv["debug"] = env_to_bool(os.environ.get("SENTRY_DEBUG"), strict=True) or False
 
     if rv["server_name"] is None and hasattr(socket, "gethostname"):
         rv["server_name"] = socket.gethostname()