[Issue]: Cannot run Keyframe Extractor task

[sypion]

Please describe your bug

Every time I attempt to manually run the keyframe extractor task, it immediately fails.

Reproduction Steps

1. Start Jellyfin server
2. Visit Admin Dashboard
3. Navigate to "Scheduled Tasks"
4. Run the Keyframe Extractor task

Jellyfin Version

10.9.0

if other:

10.9.7

Environment

- OS: Linux (Ubuntu) x64
- Linux Kernel: 5.15.0-107-generic
- Virtualization: KVM
- Clients: Browser, Windows Client
- Browser: Arc (Chromium)
- FFmpeg Version: 6
- Reverse Proxy: No
- Base URL: localhost
- Networking: Host
- Storage: local

Jellyfin logs

[2024-06-25 20:53:06.710 -07:00] [ERR] Error executing Scheduled Task
System.Text.Json.JsonException: The input does not contain any JSON tokens. Expected the input to start with a valid JSON token, when isFinalBlock is true. Path: $ | LineNumber: 0 | BytePositionInLine: 0.
 ---> System.Text.Json.JsonReaderException: The input does not contain any JSON tokens. Expected the input to start with a valid JSON token, when isFinalBlock is true. LineNumber: 0 | BytePositionInLine: 0.
   at System.Text.Json.ThrowHelper.ThrowJsonReaderException(Utf8JsonReader& json, ExceptionResource resource, Byte nextByte, ReadOnlySpan`1 bytes)
   at System.Text.Json.Utf8JsonReader.Read()
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   --- End of inner exception stack trace ---
   at System.Text.Json.ThrowHelper.ReThrowWithPath(ReadStack& state, JsonReaderException ex)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at Jellyfin.MediaEncoding.Hls.Cache.CacheDecorator.TryReadFromCache(String cachePath, KeyframeData& cachedResult)
   at Jellyfin.MediaEncoding.Hls.Cache.CacheDecorator.TryExtractKeyframes(String filePath, KeyframeData& keyframeData)
   at Jellyfin.MediaEncoding.Hls.ScheduledTasks.KeyframeExtractionScheduledTask.ExecuteAsync(IProgress`1 progress, CancellationToken cancellationToken)
   at Emby.Server.Implementations.ScheduledTasks.ScheduledTaskWorker.ExecuteInternal(TaskOptions options)
[2024-06-25 20:53:06.711 -07:00] [INF] "Keyframe Extractor" Failed after 0 minute(s) and 0 seconds

FFmpeg logs

ffmpeg version 6.0.1-Jellyfin Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 11 (Ubuntu 11.4.0-1ubuntu1~22.04)
  configuration: --prefix=/usr/lib/jellyfin-ffmpeg --target-os=linux --extra-version=Jellyfin --disable-doc --disable-ffplay --disable-ptx-compression --disable-static --disable-libxcb --disable-sdl2 --disable-xlib --enable-lto --enable-gpl --enable-version3 --enable-shared --enable-gmp --enable-gnutls --enable-chromaprint --enable-opencl --enable-libdrm --enable-libass --enable-libfreetype --enable-libfribidi --enable-libfontconfig --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libopenmpt --enable-libdav1d --enable-libsvtav1 --enable-libwebp --enable-libvpx --enable-libx264 --enable-libx265 --enable-libzvbi --enable-libzimg --enable-libfdk-aac --arch=amd64 --enable-libshaderc --enable-libplacebo --enable-vulkan --enable-vaapi --enable-amf --enable-libvpl --enable-ffnvcodec --enable-cuda --enable-cuda-llvm --enable-cuvid --enable-nvdec --enable-nvenc
  libavutil      58.  2.100 / 58.  2.100
  libavcodec     60.  3.100 / 60.  3.100
  libavformat    60.  3.100 / 60.  3.100
  libavdevice    60.  1.100 / 60.  1.100
  libavfilter     9.  3.100 /  9.  3.100
  libswscale      7.  1.100 /  7.  1.100
  libswresample   4. 10.100 /  4. 10.100
  libpostproc    57.  1.100 / 57.  1.100

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