[roll third_party/pigweed] pw_rpc: Remove legacy ResponseHandler classes

This removes the definitions of the old nanopb ResponseHandler classes
following the pw_rpc client's switch to using pw_function.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/49400

third_party/pigweed Rolled-Commits: 4bcfb45ef0934dc..223a1fbe2ede453
Roller-URL: https://ci.chromium.org/b/8842858729166058464
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8842858729166058464
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If4debbb35ae79b8fd47f8df085dfdb8bcaa009e4
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/52063
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 4bcfb45..223a1fb 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 4bcfb45ef0934dcbcfc711bac1a01c7204e83231
+Subproject commit 223a1fbe2ede4533944b76cc9c0afb055e445c06