Use android::binder::unique_fd

This brings Binder's usage in Trusty closer to Linux Binder and will
enable dropping libbase dependency.

Bug: 302723053
Test: trusty/vendor/google/aosp/scripts/build.py generic-arm64-test-debug
Change-Id: I8909eac6be3b98e4bdbba0b60369b090adc9c21d
diff --git a/app/test-app/main.cc b/app/test-app/main.cc
index 4e76380..994c00c 100644
--- a/app/test-app/main.cc
+++ b/app/test-app/main.cc
@@ -230,7 +230,7 @@
 
 static void CastAuthTest_SetUp(CastAuthTest_t* state) {
     int rc;
-    android::base::unique_fd chan;
+    android::binder::unique_fd chan;
     android::status_t status;
     android::sp<android::IBinder> root;
 
@@ -243,7 +243,7 @@
     ASSERT_NE(nullptr, state->sess.get());
 
     status = state->sess->setupPreconnectedClient(
-            std::move(chan), []() { return android::base::unique_fd(); });
+            std::move(chan), []() { return android::binder::unique_fd(); });
     ASSERT_EQ(android::OK, status);
 
     root = state->sess->getRootObject();