Bump mods/ambience from b1db88f to 4dd6f8a

Bumps [mods/ambience](https://github.com/minetest-mirrors/ambience) from `b1db88f` to `4dd6f8a`.
- [Commits](minetest-mirrors/ambience@b1db88f...4dd6f8a)

---
updated-dependencies:
- dependency-name: mods/ambience
  dependency-version: 4dd6f8a5d34b8bc02e088eabc466741df62412b8
  dependency-type: direct:production
...

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Author: dependabot[bot]