roll: pigweed pw_bluetooth: Modernize APIs

Update pw_bluetooth APIs to use:
- pw_async2
- pw_multibuf
- pw_channel
- pw::expected

New targets, headers, and types are created (with the suffix "2") to
avoid breaking existing clients of these APIs.

Original-Bug: b/350994818
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/219393
Original-Revision: a615b8bf5234f48b8a33e6c837aa7521fa80d92a

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 55164677b3a608..a615b8bf5234f4
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8731504085418812369
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Id6efc3b05f577aa62691a49c8bddd3f7644c992a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/248254
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/MODULE.bazel b/MODULE.bazel
index 1c8651b..f6a4d92 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -48,8 +48,8 @@
     module_name = "pigweed",
     # ROLL: Warning: this entry is automatically updated.
     # ROLL: Last updated 2024-11-12.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8731515121537282193.
-    commit = "55164677b3a6082fbe4cc5d08238fae8329d693e",
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8731504085418812369.
+    commit = "a615b8bf5234f48b8a33e6c837aa7521fa80d92a",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
 )
 
@@ -57,8 +57,8 @@
     module_name = "pw_toolchain",
     # ROLL: Warning: this entry is automatically updated.
     # ROLL: Last updated 2024-11-12.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8731515121537282193.
-    commit = "55164677b3a6082fbe4cc5d08238fae8329d693e",
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8731504085418812369.
+    commit = "a615b8bf5234f48b8a33e6c837aa7521fa80d92a",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
     strip_prefix = "pw_toolchain_bazel",
 )