[roll third_party/pigweed] pw_rpc: improve error handling for SendResponse

 - distinguish between encode and send errors

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/39666

third_party/pigweed Rolled-Commits: d82eb75204f545b..c08854ba38cd603
Roller-URL: https://ci.chromium.org/b/8851128406881654832
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8851128406881654832
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I10ec5fb1d9639b6496a1ad845b5c0113dba21559
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/39744
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 d82eb75..c08854b 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit d82eb75204f545b6d939a1ad6af570c2f989b621
+Subproject commit c08854ba38cd603eb60a7a6a305d1605eec2ed82