[roll third_party/pigweed] pw_rpc: Remove an edge UB case

Not all branches assign call_id. Based on cl/501757539.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126533

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 4b6c52dbc6058d2..c4c585a29871b4d
Roller-URL: https://ci.chromium.org/b/8792038176959540705
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I04dc86af78f1cb15d78f6ff5ab074fb2b3f934a4
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/126521
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 4b6c52d..c4c585a 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 4b6c52dbc6058d2f9e04f62d654f33c82e88e170
+Subproject commit c4c585a29871b4d66a38a409589c5e72e9fbe391