address unsafe usage of new static()

Problem/Motivation

When scanning Group 3.3.5 with Upgrade Status in Drupal 11, there are a few dozen warnings listed of the form,

web/modules/composer/group/src/Controller/GroupMembershipController.php 55 Unsafe usage of new static().

Steps to reproduce

In Drupal 11, use Upgrade Status to scan Group 3.3.5. Look at the identified problems.

Proposed resolution

In the 4.0 branch, use autowiring where possible; where not, use the $instance = parent::create() pattern or use self() instead of static(), as appropriate.

Remaining tasks

Make a MR. I am assigning this branch to myself until I have one ready for review.