roll: third_party/pigweed pw_proto_compiler: GN Per-target oneof API switch

Original-Bug: b/376815099

Use per target setting for enable new "oneof" protobuf encoding and
decoding API. Make it easier for downstream projects to
incrementally move to the new API.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/246572
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: 16b4bf5bc855a7d862581040cc2cc49015a90308

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 4f3b9117dfb914..16b4bf5bc855a7
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8732140892971568961
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I965109876882b6ace1e454b8577ae98984630b79
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/247013
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 4f3b911..16b4bf5 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 4f3b9117dfb9147564121ffe2eafe0c11424a384
+Subproject commit 16b4bf5bc855a7d862581040cc2cc49015a90308