Set public visibility for rtp_rtcp and video_coding targets

Though discouraged, those folders are listed in native-api

NOTRY=True

Bug: webrtc:9808
Change-Id: I9407c8d69a0d75196cfa9435f5e459264c64e046
Reviewed-on: https://webrtc-review.googlesource.com/c/103364
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24953}

modules/rtp_rtcp/BUILD.gn

@@ -9,6 +9,7 @@
 import("../../webrtc.gni")
 
 rtc_source_set("rtp_rtcp_format") {
+  visibility = [ "*" ]
   public = [
     "include/rtp_cvo.h",
     "include/rtp_header_extension_map.h",

modules/video_coding/BUILD.gn

@@ -214,6 +214,7 @@ rtc_source_set("mock_headers") {
 }
 
 rtc_source_set("codec_globals_headers") {
+  visibility = [ "*" ]
   sources = [
     "codecs/h264/include/h264_globals.h",
     "codecs/interface/common_constants.h",