Editing Invite type throws fatal error

Code review

- The patch works
- Correctly identified the changes in #3276084: Fix all dependency injection in the Invite as the source of the issue
- Undid the specific change causing the issue

Proposed improvement

There were a couple of issues with changes in #3276084:

• It does not use the the attribute named configFactory. There is a method named configFactory on FormBase. The new code used the method inherited from FormBase, $this->configFactory(), not the attribute it created to hold the service object, $this->configFactory.
• It did not need to dependancy inject config.factory, it could have directly called $this->configFactory().

I don't think we should still use dependancy injection. I propose changing the existing MR by replacing the \Drupal::config call with $this->configFactory():

    $sending_methods = $this->configFactory()
      ->get('invite.invite_sender.' . $invite_type->getType())
      ->get('sending_methods');

Opps, I think I was looking at MR 11 instead of MR 12.

So, what I propose is:

• Remove the explicite dependency injection of config.factory and remove $configFactory
• Switch the code block to use $this->configFactory()->get()

@tijsdeboeck: I didn't want to update your MR directly, that seems rude.

Attached is a patch with the changes I mentioned. It also includes removing the dependency injection for messenger. It turns out that, like config factory, one of the parent classes already includes it.

The patch:

• Removes dependency injection for config factory
• Switches to using the parent class ->configFactory() method
• Removes dependency injection for messenger
• Switches to using the parent class ->messenger() method
• Adds the missing get to the ->configFactory() call