Enable system ffmpeg

Description:

electron is not build with system's ffmpeg dut to the reason in PKGBUILD:

# [ffmpeg]="ffmpeg libavcodec.so libavcodec.so libavformat.so libavutil.so" # YouTube playback stopped working in Chromium 120

This should be possible after ffmpeg#17 (closed) is applied.

Additional info:

• package versions: electron35 35.1.5-1 , electron34 34.5.0-2 , etc...