LibAudio/Wav: Remove unused methods

Userland/Libraries/LibAudio/WavWriter.h

@@ -30,14 +30,7 @@ public:
     virtual ErrorOr<void> write_samples(ReadonlySpan<Sample> samples) override;
     virtual ErrorOr<void> finalize() override;
 
-    u32 sample_rate() const { return m_sample_rate; }
-    u16 num_channels() const { return m_num_channels; }
-    PcmSampleFormat sample_format() const { return m_sample_format; }
-
     ErrorOr<void> set_file(StringView path);
-    void set_num_channels(int num_channels) { m_num_channels = num_channels; }
-    void set_sample_rate(int sample_rate) { m_sample_rate = sample_rate; }
-    void set_sample_format(PcmSampleFormat sample_format) { m_sample_format = sample_format; }
 
 private:
     ErrorOr<void> write_header();