fix(debug): Do not consider parent loggers for debug logging (#4286)

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) will require a different fix.

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()