[roll third_party/pigweed] pw_env_setup: Don't clear gni vars in CIPD hook

Don't clear the variables in the pigweed_environment.gni file when the
CIPD post-checkout hook runs.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/105157

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 05b8e4e0567085a..3bf6cd199d754cb
Roller-URL: https://ci.chromium.org/b/8806642202452471137
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8806642202452471137
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I47dc5db80a3dc551235c5ed0c8968a1c3dd78695
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/105222
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 05b8e4e..3bf6cd1 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 05b8e4e0567085a2442ebc14720295c6b63bf3de
+Subproject commit 3bf6cd199d754cbac9692b7c4871db63a4ca6ba3