nipanel: Use typing_extensions directly

Author: bkeryan

src/nipanel/_panel.py

@@ -3,20 +3,14 @@
 import sys
 from abc import ABC
 from types import TracebackType
-from typing import TYPE_CHECKING
 
 import grpc
 from ni_measurement_plugin_sdk_service.discovery import DiscoveryClient
 from ni_measurement_plugin_sdk_service.grpc.channelpool import GrpcChannelPool
+from typing_extensions import Self
 
 from nipanel._panel_value_accessor import PanelValueAccessor
 
-if TYPE_CHECKING:
-    if sys.version_info >= (3, 11):
-        from typing import Self
-    else:
-        from typing_extensions import Self
-
 
 class Panel(PanelValueAccessor, ABC):
     """This class allows you to open a panel and specify values for its controls."""