fix(debug): Do not consider parent loggers for debug logging

This reverts commit 3793084, which made the SDK consider parent loggers when determining if the Sentry SDK should log debug messages.

However, we should not consider parent loggers, since we only want the SDK to log debug messages when configured to do so via `debug=True` (in `sentry_sdk.init`), the `SENTRY_DEBUG` environment variable, or via a specific logger configuration for `sentry_sdk.errors`. With 3793084, a custom root logger configuration would also cause SDK logs to be emitted.

The issue 3793084 was meant to fix (#3944) appears to have been caused by user error, not a bug in the SDK.

Fixes #4266

Author: szokeasaurusrex

sentry_sdk/debug.py

@@ -19,7 +19,7 @@ def filter(self, record):
 
 def init_debug_support():
     # type: () -> None
-    if not logger.hasHandlers():
+    if not logger.handlers:
         configure_logger()