roll: third_party/pigweed pw_bluetooth_sapphire: Add FIDL path for opening L2CAP channels

Implement the FIDL path for opening L2CAP channels, additionally updates
`BrEdrConnectionServer` to be named `ChannelServer`, making it generic
to any `fuchsia.bluetooth.Channel` implementation.

Test: //pw_bluetooth_sapphire/fuchsia/host/fidl:test_pkg
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/246713
Original-Revision: 447364e12c57a5651a98e93b4baddd6952631ef6

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: dea7775e165fcd..447364e12c57a5
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8731523193279357057
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I5bc0adc52bf27587cc485420cc89a1c64e2fe360
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/248031
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.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 dea7775..447364e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit dea7775e165fcd6c03143b3b2000cd5c69493643
+Subproject commit 447364e12c57a5651a98e93b4baddd6952631ef6