Java issues batch 7 (#2704) (#2707)

* snowball token language field optional (826)

* geo distance sort missing nested field (831)

* unhealthy policies nullable (834)

* missing properties from allocation record (835)

* nullable properties in transform progress (842)

* adding missing stagnating_indices field to ilm indicator

* fixing types, added creating_replicas

(cherry picked from commit 246b1a6)

Co-authored-by: Laura Trotta <[email protected]>

Author: github-actions[bot]