Bump third_party/nanopb/repo from `5fd8f04` to `cf26d28` (#31281)

Bumps [third_party/nanopb/repo](https://github.com/nanopb/nanopb) from `5fd8f04` to `cf26d28`.
- [Commits](https://github.com/nanopb/nanopb/compare/5fd8f04a48be1a250c3bbdc9f7c782ef2c372e74...cf26d28b88010dd3ac94e0cba64d4a71522154bc)

---
updated-dependencies:
- dependency-name: third_party/nanopb/repo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/nanopb/repo b/third_party/nanopb/repo
index 5fd8f04..cf26d28 160000
--- a/third_party/nanopb/repo
+++ b/third_party/nanopb/repo
@@ -1 +1 @@
-Subproject commit 5fd8f04a48be1a250c3bbdc9f7c782ef2c372e74
+Subproject commit cf26d28b88010dd3ac94e0cba64d4a71522154bc