[roll third_party/pigweed] pw_env_setup: Fix banner printing on Windows

- Fix colors load import error when runnning activate.bat on windows.
- Load PW_BRANDING_BANNER if it exist in windows_env_start.py
- Always load the branding banner files as utf-8

Original-Bug: b/289008307
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/169172

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: b3717b13619c28f..9514d6ad0ea0758
Roller-URL: https://ci.chromium.org/b/8771108881691780929
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I8a22b5b2f7495092f75a3461ee545434f837163c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/169185
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index b3717b1..9514d6a 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit b3717b13619c28f5173cba6e62b8d698a53e30be
+Subproject commit 9514d6ad0ea0758cb47650ca573d8fcccfb67209