Rename AnnouncementObserver to AnnouncementListener.

I feel this wording match java naming more closely.

Bug: 68045105
Test: VTS
Change-Id: If30fa9b356b6b45fe8853bc5194c7098d0fb2aa5
diff --git a/broadcastradio/2.0/default/BroadcastRadio.cpp b/broadcastradio/2.0/default/BroadcastRadio.cpp
index d16aaff..aa5afad 100644
--- a/broadcastradio/2.0/default/BroadcastRadio.cpp
+++ b/broadcastradio/2.0/default/BroadcastRadio.cpp
@@ -141,9 +141,9 @@
     return {};
 }
 
-Return<void> BroadcastRadio::registerAnnouncementObserver(
-    const hidl_vec<AnnouncementType>& enabled, const sp<IAnnouncementObserver>& /* cb */,
-    registerAnnouncementObserver_cb _hidl_cb) {
+Return<void> BroadcastRadio::registerAnnouncementListener(
+    const hidl_vec<AnnouncementType>& enabled, const sp<IAnnouncementListener>& /* listener */,
+    registerAnnouncementListener_cb _hidl_cb) {
     ALOGV("%s(%s)", __func__, toString(enabled).c_str());
 
     _hidl_cb(Result::NOT_SUPPORTED, nullptr);