[ray_client]: Insert decorators into the real ray module to allow for client mode (#13031)

python/ray/_raylet.pyx

@@ -107,6 +107,10 @@ from ray.exceptions import (
     TaskCancelledError
 )
 from ray.utils import decode
+from ray._private.client_mode_hook import (
+    _enable_client_hook,
+    _disable_client_hook,
+)
 import msgpack
 
 cimport cpython
@@ -558,6 +562,7 @@ cdef CRayStatus task_execution_handler(
 
     with gil:
         try:
+            client_was_enabled = _disable_client_hook()
             try:
                 # The call to execute_task should never raise an exception. If
                 # it does, that indicates that there was an internal error.
@@ -582,6 +587,8 @@ cdef CRayStatus task_execution_handler(
             else:
                 logger.exception("SystemExit was raised from the worker")
                 return CRayStatus.UnexpectedSystemExit()
+        finally:
+            _enable_client_hook(client_was_enabled)
 
     return CRayStatus.OK()