Cannot remove enum singleton

[jlindblad]

Describe the bug
Removing an enum singleton component does not work. It is my assumption that the behavior should be the same as for a struct singleton.

To Reproduce
The following code will fail on the second assert.

#include <cassert>
#include <flecs.h>

struct MyStruct {
  int a = 0;
};
enum MyEnum { a = 0, b };

int main() {
  flecs::world ecs;

  ecs.set<MyStruct>({});
  ecs.remove<MyStruct>();
  bool has_struct = ecs.has<MyStruct>();
  assert(!has_struct);

  ecs.set<MyEnum>(MyEnum::a);
  ecs.remove<MyEnum>();
  bool has_enum = ecs.has<MyEnum>();
  assert(!has_enum);

  return 0;
}

Expected behavior
The enum singleton should be removed.