Prepare for splitting FrameType into AudioFrameType and VideoFrameType

This cl deprecates the FrameType enum, and adds aliases AudioFrameType
and VideoFrameType.

After downstream usage is updated, the enums will be separated
and be moved out of common_types.h.

Bug: webrtc:6883
Change-Id: I2aaf660169da45f22574b4cbb16aea8522cc07a6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/123184
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27011}
diff --git a/modules/audio_coding/test/TestVADDTX.cc b/modules/audio_coding/test/TestVADDTX.cc
index 7c04b22..b22e97e 100644
--- a/modules/audio_coding/test/TestVADDTX.cc
+++ b/modules/audio_coding/test/TestVADDTX.cc
@@ -33,7 +33,7 @@
   ResetStatistics();
 }
 
-int32_t ActivityMonitor::InFrameType(FrameType frame_type) {
+int32_t ActivityMonitor::InFrameType(AudioFrameType frame_type) {
   counter_[frame_type]++;
   return 0;
 }