[roll third_party/pigweed] pw_log_rpc: Release payload buffer when active

The RpcLogDrain::server_writer_ can be closed asynchronously, by the
client. Only release the payload buffer if the writer is still active,
in order to leave the writer in a replaceable state.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/73500

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 38fee79685436e1..b5fa5d338236851
Roller-URL: https://ci.chromium.org/b/8827930730555067313
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8827930730555067313
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ie16598babd1206db3f48dd8460b0652db6dbdcab
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/73960
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 38fee79..b5fa5d3 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 38fee79685436e1b2e0d69919150e639b57d1dd7
+Subproject commit b5fa5d3382368516cf8a11204371c0cde4eb8bd4