Set the sample rate for MP3 exports (#7998)

Sets the MP3 export sample rate to that of the engine's rate.


Co-authored-by: Dalton Messmer <messmer.dalton@gmail.com>

src/core/audio/AudioFileMP3.cpp

@@ -117,6 +117,7 @@ bool AudioFileMP3::initEncoder()
 
 	lame_set_VBR(m_lame, vbr_off);
 	lame_set_brate(m_lame, bitRate);
+	lame_set_in_samplerate(m_lame, static_cast<int>(getOutputSettings().getSampleRate()));
 
 	// Add a comment
 	id3tag_init(m_lame);