roll: third_party/pigweed 19bb20e..9e4c976 (6 commits)

9e4c976:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/253264 pw_thread: Move ThreadCore logic out of pw::Thread
019e35f:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/253555 pw_bluetooth_proxy: Include l2cap_channel_event.h where it is used
f138221:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/253552 pw_thread_freertos: Remove variable when it is not used
a957859:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/253514 pw_thread: Adding missing ThreadCore deps or migrate to pw::Function
07d2258:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/253512 Revert "docs: Add rustdocs to Bazel build"
9aceb7c:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/231912 pw_crypto: Implement Mbed-TLS backend for AES

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 19bb20e57146c9..9e4c976345d4d2
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8728865789067666913
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Id28a0a2ee8ec77ad4ba4948de0d827afbae07ad5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/kudzu/+/253028
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 19bb20e..9e4c976 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 19bb20e57146c9280c22f815f6e46ded2dbf0e64
+Subproject commit 9e4c976345d4d2de321e17853e9fb86493ff2200