CCR follower stats can return information for persistent tasks that are in the process of being cleaned up. This is problematic for tests where CCR follower indices have been deleted, but their persistent follower task is only cleaned up asynchronously afterwards. If one of the following tests then accesses the follower stats, it might still get the stats for that follower task.
In addition, some tests were not cleaning up their auto-follow patterns, leaving orphaned patterns behind. Other tests cleaned up their auto-follow patterns. As always the same name was used, it just depended on the test execution order whether this led to a failure or not. This commit fixes the offensive tests, and will also automatically remove auto-follow-patterns at the end of tests, like we do for many other features.
Closes #48700
