Rust protobuf 2->3: Update build system

tldr: remove protobuf2 from Android Rust and upgrade everything to pb3.

These commits update:
- The grpcio rust crate to use protobuf 3
- The build system to always use the new libprotobuf (pb3) instead of the _deprecated variant (for pb2); they also force-enable libprotobuf everywhere, ignoring the use_protobuf3 flag, removes the tests related to pb2
- The following modules, which required syntax changes:
-- packages/modules/Bluetooth
-- device/google/cuttlefish
-- vendor/auto

Bug: 308790516
Test: m rust
Ignore-AOSP-First: must be done in main to upgrade cuttlefish+vendor with the rest all at once
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:7d0783ce22b3d7d369786d4b16067c79c033185b)
Merged-In: I1d07c433aca41ccfe2e710821cf930c413dc12d6

Change-Id: I1d07c433aca41ccfe2e710821cf930c413dc12d6

1 files changed, 0 insertions, 6 deletions

diff --git a/rust/testing.go b/rust/testing.go
index 3fe751e17..0b34c9732 100644
--- a/rust/testing.go
+++ b/rust/testing.go
@@ -133,12 +133,6 @@ func GatherRequiredDepsForTest() string {
 			host_supported: true,
 		}
 		rust_library {
-			name: "libprotobuf_deprecated",
-			crate_name: "protobuf",
-			srcs: ["foo.rs"],
-			host_supported: true,
-		}
-		rust_library {
 			name: "libgrpcio",
 			crate_name: "grpcio",
 			srcs: ["foo.rs"],