Make sdk/android:{audio,video}_api_java publicly visible.

Bug: None
Change-Id: I7a2b4d643fa776b4bf2ab3a4860bbc8892dc1a86
Reviewed-on: https://webrtc-review.googlesource.com/c/123229
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26732}

sdk/android/BUILD.gn

@@ -209,6 +209,7 @@ if (is_android) {
   }
 
   rtc_android_library("audio_api_java") {
+    visibility = [ "*" ]
     java_files = [
       "api/org/webrtc/audio/AudioDeviceModule.java",
       "api/org/webrtc/AudioDecoderFactoryFactory.java",
@@ -222,6 +223,7 @@ if (is_android) {
   }
 
   rtc_android_library("video_api_java") {
+    visibility = [ "*" ]
     java_files = [
       "api/org/webrtc/EncodedImage.java",
       "api/org/webrtc/VideoCodecInfo.java",