[roll third_party/pigweed] pw_software_update: fixup update backend API

Renames the backend header to match the object name.

Adjusts the FinalizeUpdate() API to use Status again to report
finalize failures before the reboot.

Also changes ApplyTargetFile() to be pure virtual.

Changes the backend API to use the Manifest object instead of the
nanopb struct for the manifest.

Moves the Manifest definition to a separate header.

Adds missing pw_protobuf dependency.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/61820

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: e0b03f5a2179d41..a9133b059eda99d
Roller-URL: https://ci.chromium.org/b/8835416818833490737
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8835416818833490737
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I91654a999ed64bc2f61e5bf0b28ef115a5e68866
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/61766
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 e0b03f5..a9133b0 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit e0b03f5a2179d41753e21680aa990d77a732bc72
+Subproject commit a9133b059eda99d6e3175464bc61d4feffba5f2f