TaskGroup actions could miss some TIs

Clearing or Marking as Success/Fail a taskgroup could actually miss some TIs.

In the current implementation, we fetch the group TIs by filtering TIs on the `taskDisplayNamePattern` (groupId) pattern.

The result is paginated and we only retrieve the first 50 results. If the group holds more than page_size items, some will be skipped.

Start by locating the TaskGroup action code and the task-instance query filtering on taskDisplayNamePattern (groupId), then trace how pagination is applied. Reproduce the issue with a group containing more than 50 task instances and verify that clearing or marking success or failure reaches every matching instance, including those beyond the first page.

Written by the indexing model from the issue text.