[roll third_party/pigweed] pw_function: Fix for move-only types

- Add std::forward to support move-only function arguments.
- Mark default constructors constexpr.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/79501

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 1efc17b5264a19b..1af214dea2172dc
Roller-URL: https://ci.chromium.org/b/8824580842396203617
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8824580842396203617
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I01b43557224bbfa9249ad9b37c71623ad0a92246
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/79600
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 1efc17b..1af214d 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1efc17b5264a19b7aa8cbe4e3e7dfc5d1abcbe1a
+Subproject commit 1af214dea2172dccbb43bad6c62f1275e8b29e97