Add check for null VMobject in shader init

Author: 3b1b

manimlib/mobject/types/vectorized_mobject.py

@@ -1293,7 +1293,8 @@ def init_shader_data(self, ctx: Context):
             self.stroke_shader_wrapper,
         ]
         for sw in self.shader_wrappers:
-            rep = self.family_members_with_points()[0]
+            family = self.family_members_with_points()
+            rep = family[0] if family else self
             for old, new in rep.shader_code_replacements.items():
                 sw.replace_code(old, new)