[roll third_party/pigweed] pw_env_setup: Move clear of PW_BRANDING_BANNER

Clear PW_BRANDING_BANNER and PW_BRANDING_BANNER_COLOR in deactivate not
cleanup.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/75560

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: a40ce7674c9522b..9a3b69b93178748
Roller-URL: https://ci.chromium.org/b/8827288452631850033
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8827288452631850033
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I486b6e47c9411454492ee8e5a850071bfeb08944
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/75760
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 a40ce76..9a3b69b 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit a40ce7674c9522b46aa99d13507140540a0f9484
+Subproject commit 9a3b69b93178748404789da51026de03f4f0bbae