[Python Misc] Revert change to print backtrace in server (#34877)

Fix: https://github.com/grpc/grpc/issues/34853

In order to make debugging easier, we have begun printing backtraces in servers. However, this change has the unintended consequence of printing errors to stderr by default, which may not be expected by some users.

This PR reverts the change. We recommend that users set up a logging sink if they want to see errors. We will add this to our documentation later.

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Closes #34877

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/34877 from XuanWang-Amos:revert_print_backtrace_change 8942308784
PiperOrigin-RevId: 588885550

src/python/grpcio/grpc/_server.py

@@ -579,7 +579,7 @@ def _call_behavior(
                                 exception.__traceback__,
                             )
                         )
-                    traceback.print_exc()
+                        traceback.print_exc()
                     _LOGGER.exception(details)
                     _abort(
                         state,