Revert "Fix type hints for RendererGL.gl"

This reverts commit 82224a2.

Author: diegoferigo-rai

newton/_src/viewer/gl/opengl.py

@@ -17,8 +17,6 @@
 import io
 import os
 import sys
-from types import ModuleType
-from typing import TYPE_CHECKING, ClassVar
 
 import numpy as np
 import warp as wp
@@ -33,10 +31,6 @@
     ShadowShader,
 )
 
-if TYPE_CHECKING:
-    from pyglet import gl
-
-
 ENABLE_CUDA_INTEROP = True
 ENABLE_GL_CHECKS = False
 
@@ -777,8 +771,7 @@ def render(self):
 
 
 class RendererGL:
-    # Class-level variable to hold the imported module
-    gl: ClassVar["ModuleType | type[gl]"] = None  # pyright: ignore[reportAssignmentType, reportInvalidTypeForm]
+    gl = None  # Class-level variable to hold the imported module
 
     @classmethod
     def initialize_gl(cls):