Fixes #20929: Require render_config permission for UI config rendering (#20975)

* Closes #20929: Require render_config permission for UI config rendering

- Modified `ObjectRenderConfigView.has_permission()` to require both view and render_config permissions
- Added `remove_permissions()` test helper to remove permissions from existing ObjectPermission objects
- Added regression tests for Device and VirtualMachine render-config permission enforcement

The `render_config` permission action was introduced in #16681 for API endpoints. This extends PR_7604_description
to the UI render-config tabs, preventing users from viewing rendered configurations without explicit permission.

* Address PR feedback

* Address PR feedback

netbox/utilities/testing/base.py

@@ -67,6 +67,16 @@ class TestCase(_TestCase):
             obj_perm.users.add(self.user)
             obj_perm.object_types.add(object_type)
 
+    def remove_permissions(self, *names):
+        """
+        Remove a set of permissions from the test user. Accepts permission names in the form <app>.<action>_<model>.
+        """
+        for name in names:
+            object_type, action = resolve_permission_type(name)
+            ObjectPermission.objects.filter(
+                actions__contains=[action], object_types=object_type, users=self.user
+            ).delete()
+
     #
     # Custom assertions
     #