[roll third_party/pigweed] pw_thread_embos: Add thread snapshot support

Adds Snapshot integration for embos thread state.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/52040

third_party/pigweed Rolled-Commits: 1807962d1886441..952f2d5865cb623
Roller-URL: https://ci.chromium.org/b/8842219877591802080
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8842219877591802080
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia68f815e804cc69fd369246efcf48624332090bd
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/52503
Reviewed-by: 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 1807962..952f2d5 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1807962d1886441c89ad5091a00b7f6afb202e4d
+Subproject commit 952f2d5865cb623237d837c2926fef05186b4cee