[roll third_party/pigweed] pw_rpc: Common Endpoint base for Server/Client

- Create pw::rpc::internal::Endpoint class that serves as the common
  base for the Server and Client. It manages the internal
  lists of active calls and available RPC channels.
- Refactor the pw::rpc::Server to derive from Endpoint. The Client will
  be refactored to use Endpoint in a subsequent change.
- No longer send responses to corrupt packets. If packets are being
  corrupted, a response isn't likely to be helpful.
- Remove the unnecessary internal::Server class.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/60185

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 8c70fccf01bcf48..ddfc077efac67c3
Roller-URL: https://ci.chromium.org/b/8836429862039615905
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8836429862039615905
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I537071f7f6b4674b84965ccf6681d3a8c5635cc3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/60491
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 8c70fcc..ddfc077 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 8c70fccf01bcf48811fe53313c932bcdccabb4dd
+Subproject commit ddfc077efac67c34b3222b9dfc48f504c477ec0b