[third_party/pigweed] Roll 3 commits

9c7d87957171705 pw_unit_test: Ensure alignment of test fixtures
969c75d77d2fbcf pw_transfer: Fix transfer_thread_test initializati
2e46e4ac3dfbbfc pw_config_loader: Remove unnecessary dep

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 1edf35a4ff1c563..9c7d87957171705
Roller-URL: https://ci.chromium.org/b/8747654085648819857
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I31f5cb87997ec4aef69c9da86dc8bd0d6094c5f8
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/210359
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 1edf35a..9c7d879 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1edf35a4ff1c5638680ee48ea41e2b35c54c556f
+Subproject commit 9c7d879571717058f000a04109204a381aa3d4c1