[roll third_party/pigweed] pw_sync: Add const operators

Add const operators for operator-> and operator*

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126220

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: eac2c8ab9398fc8..4f10c431a51eb19
Roller-URL: https://ci.chromium.org/b/8792320581494771713
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ib806d06da2c624bb59e9dab480757ffe5188d94a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/126342
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index eac2c8a..4f10c43 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit eac2c8ab9398fc84057b3d5ad632aa23848bf39b
+Subproject commit 4f10c431a51eb1929944653645bca992c17b140b