libobs: Move encoded_callback_t to obs-internal.h

Allows it to be used in multiple source files.

libobs/obs-internal.h

@@ -596,6 +596,8 @@ extern float obs_source_get_target_volume(obs_source_t *source,
 /* ------------------------------------------------------------------------- */
 /* outputs  */
 
+typedef void (*encoded_callback_t)(void *data, struct encoder_packet *packet);
+
 struct obs_weak_output {
 	struct obs_weak_ref ref;
 	struct obs_output *output;

libobs/obs-output.c

@@ -961,8 +961,6 @@ static void default_raw_audio_callback(void *param, size_t mix_idx,
 	UNUSED_PARAMETER(mix_idx);
 }
 
-typedef void (*encoded_callback_t)(void *data, struct encoder_packet *packet);
-
 static inline void start_audio_encoders(struct obs_output *output,
 		encoded_callback_t encoded_callback)
 {