Draft: chore: bump zoekt image to v1.11.2 and chart version to 3.8.5

What does this MR do and why?

Bumps the `gitlab-zoekt` image tag from `v1.11.1` to `v1.11.2` and chart version from `3.8.3` to `3.8.5`.

`v1.11.2` is a backport of refactor: bump schemaVersion to initiate force reindexing which fixes a bug where the Zoekt indexer incorrectly performs an incremental index after a force push, resulting in stale or missing search results for self-managed customers on GitLab 18.10.

References

• Original issue: gitlab-org/gitlab#593947 (closed)
• Original fix: gitlab-org/gitlab-zoekt-indexer@4cd14d64

Backport chain for 18.10 (SM)

1. ✅ `gitlab-zoekt-indexer` — cherry-picked fix onto `v1.11.1`, tagged `v1.11.2`
2. ✅ `gitlab-org/build/CNG` — gitlab-org/build/CNG!2904 (merged), builds `cng/gitlab-zoekt:v1.11.2` on `18-10-stable`
3. ⏳ `gitlab-org/gitlab` — MR on `18-10-stable-ee` bumping `GITLAB_ZOEKT_VERSION` to `1.11.2`
4. ⭐ `cloud-native/charts/gitlab-zoekt` — this MR, bump chart to `3.8.5` with image `v1.11.2`
5. ⏳ `gitlab-org/charts/gitlab` — MR on `9-10-stable` bumping `gitlab-zoekt` to `3.8.5`