Don't move const assignments

[simonihmig]

Before:

moduleForComponent('bs-form/element', 'Integration | Component | bs-form/element', {
  integration: true
});

const foo = 'bar';

After:

module('Integration | Component | bs-form/element', function(hooks) {
  setupRenderingTest(hooks);

  const foo = 'bar';
});

The const assignment is moved to the module callback, which might break some ESLint setups (prefering let over const, const only at module scope).

I think it would make sense to leave any const assignments at the module scope, and not move them into the callback function. Rather minor issue though!