ilbc: click at the beginning of the audio

[ami_stuff]

ffmpeg decodes attached sample with a click at the beginning

qt decodes the file without the click (qt's output also attached)

./ffmpeg -i 2s.mov -y out.wav
ffmpeg version N-112728-g409b29d3f9 Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 11 (Ubuntu 11.4.0-1ubuntu1~22.04)
  configuration: 
  libavutil      58. 32.100 / 58. 32.100
  libavcodec     60. 33.100 / 60. 33.100
  libavformat    60. 17.100 / 60. 17.100
  libavdevice    60.  4.100 / 60.  4.100
  libavfilter     9. 13.100 /  9. 13.100
  libswscale      7.  6.100 /  7.  6.100
  libswresample   4. 13.100 /  4. 13.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2s.mov':
  Metadata:
    major_brand     : qt  
    minor_version   : 537199360
    compatible_brands: qt  
    creation_time   : 2023-11-21T13:32:13.000000Z
  Duration: 00:00:02.20, start: 0.000000, bitrate: 18 kb/s
  Stream #0:0[0x1](eng): Audio: ilbc (ilbc / 0x63626C69), 8000 Hz, mono, s16 (default)
    Metadata:
      creation_time   : 2023-11-21T13:32:13.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
Stream mapping:
  Stream #0:0 -> #0:0 (ilbc (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, wav, to 'out.wav':
  Metadata:
    major_brand     : qt  
    minor_version   : 537199360
    compatible_brands: qt  
    ISFT            : Lavf60.17.100
  Stream #0:0(eng): Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, s16, 128 kb/s (default)
    Metadata:
      creation_time   : 2023-11-21T13:32:13.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
      encoder         : Lavc60.33.100 pcm_s16le
[out#0/wav @ 0x560f4951cc80] video:0kB audio:34kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.221591%
size=      34kB time=00:00:02.18 bitrate= 129.5kbits/s speed= 177x