[roll third_party/pigweed] pw_ide: Remove VSIX installation stuff

The VS Code extension is now published to the Marketplace, so we don't
need to support installing directly from a VSIX file.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/184991

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 7c4f734ccdd67ed..8ffa93fc685c320
Roller-URL: https://ci.chromium.org/b/8761772899642608433
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ib50fc645977f39470f6b837216955228619b81b6
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/185018
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 7c4f734..8ffa93f 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 7c4f734ccdd67ed52b5a86eecbbf6e60bb7db183
+Subproject commit 8ffa93fc685c320e93cb93626f64afac49aea318