fix: swap to `jellyfin-ffmpeg5` (#9256)

Dockerfile

@@ -37,7 +37,7 @@ RUN apt-get update \
  && apt-get update \
  && apt-get install --no-install-recommends --no-install-suggests -y \
    mesa-va-drivers \
-   jellyfin-ffmpeg \
+   jellyfin-ffmpeg5 \
    openssl \
    locales \
 # Intel VAAPI Tone mapping dependencies: