ClusterReindexingService should consider space for partial reindexing as well
Summary
Preflight check should also consider the total available space for partial cluster reindexing. Currently, it is just considering the total available space for full cluster reindexing. Related code: https://gitlab.com/gitlab-org/gitlab/-/blob/08224960b41282b112bc12be1491a67ca5d60441/ee/app/services/elastic/cluster_reindexing_service.rb#L64
First observed here: gitlab-com/gl-infra/production#16055 (comment 1640977381)
Steps to reproduce
What is the current bug behavior?
Currently, cluster_reindexing_service is just considering the total available space for full cluster reindexing
What is the expected correct behavior?
Should also consider the total available space for partial cluster reindexing