Improve group deletion

[armenzg]

Move these lines:

sentry/src/sentry/api/helpers/group_index/delete.py

Lines 85 to 94 in f39a2b5

	# Tell seer to delete grouping records for these groups
	call_delete_seer_grouping_records_by_hash(error_ids)
	# Removing GroupHash rows prevents new events from associating to the groups
	# we just deleted.
	GroupHash.objects.filter(project_id=project.id, group__id__in=group_ids).delete()
	# We remove `GroupInbox` rows here so that they don't end up influencing queries for
	# `Group` instances that are pending deletion
	GroupInbox.objects.filter(project_id=project.id, group__id__in=group_ids).delete()

into src/sentry/deletions/tasks/groups.py

If the aforementioned lines failed to execute, it will prevent the deletion of the groups.

This can be seen in this event (internal link).